from docx import Document
from docx.shared import Pt, Inches, RGBColor
from docx.enum.text import WD_ALIGN_PARAGRAPH
from docx.oxml.ns import qn
from docx.oxml import OxmlElement
import copy

doc = Document()

# --- PAGE SETUP: A4 with 1-inch margins ---
section = doc.sections[0]
section.page_height = Inches(11.69)
section.page_width  = Inches(8.27)
section.left_margin   = Inches(1.0)
section.right_margin  = Inches(1.0)
section.top_margin    = Inches(1.0)
section.bottom_margin = Inches(1.0)

# --- DEFAULT FONT: Times New Roman 12pt ---
normal_style = doc.styles['Normal']
normal_style.font.name = 'Times New Roman'
normal_style.font.size = Pt(12)

# Helper: add a heading with custom formatting
def add_section_heading(doc, text, level=1, bold=True, size=14, color=None, underline=False, center=False):
    para = doc.add_paragraph()
    run = para.add_run(text)
    run.bold = bold
    run.font.name = 'Times New Roman'
    run.font.size = Pt(size)
    run.underline = underline
    if color:
        run.font.color.rgb = RGBColor(*color)
    if center:
        para.alignment = WD_ALIGN_PARAGRAPH.CENTER
    return para

# Helper: add body text paragraph
def add_body(doc, text, bold=False, italic=False, first_line_indent=True):
    para = doc.add_paragraph()
    run = para.add_run(text)
    run.bold = bold
    run.italic = italic
    run.font.name = 'Times New Roman'
    run.font.size = Pt(12)
    para.paragraph_format.space_after = Pt(6)
    if first_line_indent:
        para.paragraph_format.first_line_indent = Inches(0.3)
    return para

# Helper: add bullet point
def add_bullet(doc, text, bold_prefix=None):
    para = doc.add_paragraph(style='List Bullet')
    if bold_prefix:
        run_bold = para.add_run(bold_prefix)
        run_bold.bold = True
        run_bold.font.name = 'Times New Roman'
        run_bold.font.size = Pt(12)
        run_rest = para.add_run(text)
        run_rest.font.name = 'Times New Roman'
        run_rest.font.size = Pt(12)
    else:
        run = para.add_run(text)
        run.font.name = 'Times New Roman'
        run.font.size = Pt(12)
    para.paragraph_format.space_after = Pt(4)
    return para

def add_sub_bullet(doc, text, bold_prefix=None):
    para = doc.add_paragraph(style='List Bullet 2')
    if bold_prefix:
        run_bold = para.add_run(bold_prefix)
        run_bold.bold = True
        run_bold.font.name = 'Times New Roman'
        run_bold.font.size = Pt(11)
        run_rest = para.add_run(text)
        run_rest.font.name = 'Times New Roman'
        run_rest.font.size = Pt(11)
    else:
        run = para.add_run(text)
        run.font.name = 'Times New Roman'
        run.font.size = Pt(11)
    para.paragraph_format.space_after = Pt(3)
    return para

# =====================================================================
# TITLE
# =====================================================================
title_para = doc.add_paragraph()
title_para.alignment = WD_ALIGN_PARAGRAPH.CENTER
title_run = title_para.add_run("CELL CYCLE")
title_run.bold = True
title_run.font.name = 'Times New Roman'
title_run.font.size = Pt(18)
title_run.font.color.rgb = RGBColor(0, 70, 127)

subtitle_para = doc.add_paragraph()
subtitle_para.alignment = WD_ALIGN_PARAGRAPH.CENTER
subtitle_run = subtitle_para.add_run("First Year MDS Oral Pathology – Applied Basic Science Examination\n10 Marks Answer")
subtitle_run.font.name = 'Times New Roman'
subtitle_run.font.size = Pt(11)
subtitle_run.italic = True
subtitle_run.font.color.rgb = RGBColor(80, 80, 80)

doc.add_paragraph()  # spacer

# =====================================================================
# 1. SYNOPSIS
# =====================================================================
add_section_heading(doc, "1. SYNOPSIS", level=1, size=13, bold=True,
                    color=(0, 70, 127), underline=True)

add_body(doc,
    "The cell cycle is the ordered series of events by which a somatic cell duplicates its genome and "
    "divides into two daughter cells. It is divided into four sequential phases: G1 (Gap 1), S (Synthesis), "
    "G2 (Gap 2), and M (Mitosis), with a non-dividing state termed G0. Progression through these phases "
    "is driven by cyclin/cyclin-dependent kinase (CDK) complexes and is regulated by a network of "
    "checkpoint surveillance systems. Tumor suppressor proteins — principally RB and p53 — and CDK "
    "inhibitors (CDKIs) enforce quality control at key transition points. In oral pathology, dysregulation "
    "of the cell cycle underlies the pathogenesis of oral epithelial dysplasia, oral submucous fibrosis, "
    "odontogenic tumors, and oral squamous cell carcinoma (OSCC). Understanding cell cycle biology "
    "is therefore fundamental to the interpretation of histopathological changes, molecular diagnostics, "
    "and targeted therapeutic strategies in oral medicine."
)

doc.add_paragraph()

# =====================================================================
# 2. INTRODUCTION
# =====================================================================
add_section_heading(doc, "2. INTRODUCTION", level=1, size=13, bold=True,
                    color=(0, 70, 127), underline=True)

add_body(doc,
    "The growth and reproduction of all living organisms ultimately depends on the ability of cells to "
    "duplicate their contents and divide — a process collectively known as the cell cycle. The term was "
    "introduced by Howard and Pelc (1953), who first described DNA synthesis as a discrete phase (S phase) "
    "separated from mitosis by gap phases."
)
add_body(doc,
    "In adult tissues, most cells are in a non-dividing quiescent state (G0). Under the influence of "
    "appropriate growth signals, cells exit G0 and re-enter the cell cycle. The decision to proliferate is "
    "irreversible beyond the G1 restriction point. Once committed, cells proceed through DNA replication "
    "in S phase, prepare for mitosis in G2, and ultimately divide in M phase. The entire process in "
    "mammalian cells takes approximately 18–24 hours, with G1 being the most variable phase."
)
add_body(doc,
    "In the context of oral pathology, the cell cycle assumes paramount importance because oral mucosal "
    "epithelium is a labile tissue that constantly undergoes renewal. Disruption of cell cycle regulation "
    "by carcinogens, viral oncoproteins (e.g., HPV E6/E7), or genetic mutations transforms this orderly "
    "proliferative program into uncontrolled growth, which is the hallmark of neoplasia. From odontogenic "
    "cyst lining epithelium to oral squamous cell carcinoma, virtually every proliferative lesion of the "
    "oral cavity can be understood through the lens of cell cycle biology."
)

doc.add_paragraph()

# =====================================================================
# 3. MAIN ANSWER CONTENTS
# =====================================================================
add_section_heading(doc, "3. MAIN ANSWER CONTENTS", level=1, size=13, bold=True,
                    color=(0, 70, 127), underline=True)

# --- 3.1 PHASES ---
add_section_heading(doc, "3.1  Phases of the Cell Cycle", size=12, bold=True, underline=False)

add_body(doc,
    "Following entry into the cell cycle, normal cells undergo a tightly choreographed sequence of events "
    "leading to DNA replication and cell division. These events occur in four distinct phases: G1, S, G2, "
    "and M; quiescent cells not actively proliferating reside in the G0 state."
    " (Robbins & Kumar Basic Pathology, 10th ed.)"
)

add_bullet(doc, "Gap 1 (G1) Phase:", bold_prefix="")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "G1 is the longest and most variable phase (typically 8–10 hours in rapidly dividing cells). "
    "During G1, the cell grows in size, synthesizes RNA and proteins required for DNA replication, "
    "and responds to mitogenic signals. It contains the critically important Restriction Point (R-point) — "
    "the stage at which the cell is committed to advance into S phase independent of external growth factors."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "S (Synthesis) Phase:", bold_prefix="")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "DNA synthesis occurs during S phase (approximately 6–8 hours). Each chromosome is replicated "
    "precisely once, producing two sister chromatids. The quality of DNA replication is monitored by "
    "the S-phase DNA damage checkpoint."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "Gap 2 (G2) Phase:", bold_prefix="")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "G2 (approximately 4–6 hours) is the interval between S phase and mitosis. The cell continues "
    "to grow and synthesizes proteins necessary for mitosis. The G2/M checkpoint ensures accurate "
    "completion of DNA replication before cell division."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "M (Mitosis) Phase:", bold_prefix="")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "Mitosis (~1 hour) involves the sequential stages of prophase (chromosome condensation, nuclear "
    "envelope breakdown, spindle formation), metaphase (chromosomal alignment at equatorial plate), "
    "anaphase (sister chromatid separation to poles), and telophase (nuclear envelope reformation, "
    "cytokinesis). A spindle assembly checkpoint ensures chromosomes are attached to spindle fibers "
    "before segregation."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "G0 (Quiescence):", bold_prefix="")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "Cells that exit the cycle enter the G0 state. Labile cells (oral epithelium, bone marrow) re-enter "
    "cycle rapidly; stable cells (hepatocytes, fibroblasts) re-enter slowly on demand; permanent cells "
    "(neurons, cardiac myocytes) are irreversibly G0."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

doc.add_paragraph()

# --- 3.2 CYCLINS, CDKs, CDKIs ---
add_section_heading(doc, "3.2  Molecular Regulators: Cyclins, CDKs, and CDK Inhibitors", size=12, bold=True)

add_body(doc,
    "Cell cycle progression is driven by proteins called cyclins — named for their cyclic rise and fall "
    "in concentration — and their partner enzymes, cyclin-dependent kinases (CDKs). Constitutively "
    "synthesized CDKs are inactive until they form complexes with the appropriate cyclin. Transient "
    "accumulation of a cyclin activates its CDK partner; once the CDK completes phosphorylation of its "
    "target substrates, cyclin is rapidly degraded via ubiquitin-mediated proteolysis, and CDK activity "
    "abates. More than 15 cyclins have been identified, with D, E, A, and B appearing sequentially. "
    "(Robbins, Cotran & Kumar Pathologic Basis of Disease, 10th ed.)"
)

# Table of cyclin-CDK complexes
table = doc.add_table(rows=6, cols=3)
table.style = 'Table Grid'
# Header row
hdr_cells = table.rows[0].cells
hdr_cells[0].text = 'Phase'
hdr_cells[1].text = 'Cyclin/CDK Complex'
hdr_cells[2].text = 'Function'
for cell in hdr_cells:
    for para in cell.paragraphs:
        for run in para.runs:
            run.bold = True
            run.font.name = 'Times New Roman'
            run.font.size = Pt(11)
    cell.paragraphs[0].alignment = WD_ALIGN_PARAGRAPH.CENTER

# Data rows
data = [
    ("G1", "Cyclin D – CDK4/CDK6", "Phosphorylates RB protein; initiates G1/S checkpoint passage"),
    ("Late G1", "Cyclin E – CDK2", "Completes RB phosphorylation; commits cell to S phase"),
    ("S phase", "Cyclin A – CDK2", "Initiates and regulates DNA replication"),
    ("G2/M", "Cyclin A – CDK1", "Active in late S and G2"),
    ("M phase", "Cyclin B – CDK1 (MPF)", "Entry and progression through mitosis; promotes nuclear envelope breakdown"),
]
for i, (phase, complex_, func) in enumerate(data, start=1):
    row_cells = table.rows[i].cells
    row_cells[0].text = phase
    row_cells[1].text = complex_
    row_cells[2].text = func
    for cell in row_cells:
        for para in cell.paragraphs:
            for run in para.runs:
                run.font.name = 'Times New Roman'
                run.font.size = Pt(10)

doc.add_paragraph()

add_body(doc,
    "CDK Inhibitors (CDKIs): Two families of CDKIs regulate CDK activity. The INK4 family (p15, p16/CDKN2A, "
    "p18, p19) specifically inhibits cyclin D-CDK4/6 complexes. The CIP/KIP family (p21/CDKN1A, p27, p57) "
    "broadly inhibits all CDK complexes. These CDKIs are tumor suppressors; their loss is a critical event "
    "in oncogenesis."
)

doc.add_paragraph()

# --- 3.3 CHECKPOINTS ---
add_section_heading(doc, "3.3  Cell Cycle Checkpoints", size=12, bold=True)

add_body(doc,
    "Surveillance mechanisms embedded within the cell cycle detect DNA damage or chromosomal errors. These "
    "quality-control checkpoints ensure that cells with genetic imperfections do not complete replication "
    "or division. When a checkpoint is activated, cell cycle progression is halted and DNA repair is "
    "initiated; if damage is irreparable, the cell undergoes apoptosis or senescence."
)

add_bullet(doc, "G1/S Checkpoint (Restriction Point): ", bold_prefix="G1/S Checkpoint (Restriction Point): ")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "The most important checkpoint. It monitors DNA integrity and cellular growth status before committing "
    "to DNA replication. Regulated by the RB–E2F pathway and p53–p21 axis. Virtually all cancers harbor "
    "lesions that disable this checkpoint."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "Intra-S Phase Checkpoint: ", bold_prefix="Intra-S Phase Checkpoint: ")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run("Monitors ongoing DNA replication fidelity; detects replication fork stalling.")
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "G2/M Checkpoint: ", bold_prefix="G2/M Checkpoint: ")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "Ensures accurate DNA replication before cell division. Activated by ATM/ATR kinases in response "
    "to double-strand DNA breaks. Prevents cells with incompletely replicated DNA from entering mitosis."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

add_bullet(doc, "Spindle Assembly Checkpoint (SAC): ", bold_prefix="Spindle Assembly Checkpoint (SAC): ")
para = doc.add_paragraph(style='List Bullet 2')
r = para.add_run(
    "During metaphase, prevents anaphase onset until all chromosomes are correctly attached to "
    "spindle microtubules via kinetochores. Mediated by the mitotic checkpoint complex (MCC) involving "
    "MAD2, BUBR1, and BUB3 proteins. Defects lead to aneuploidy."
)
r.font.name = 'Times New Roman'; r.font.size = Pt(12)

doc.add_paragraph()

# --- 3.4 RB PROTEIN ---
add_section_heading(doc, "3.4  Role of the Retinoblastoma Protein (RB) — Governor of the Cell Cycle", size=12, bold=True)

add_body(doc,
    "The RB protein is a DNA-binding protein that serves as the central integrator of signals regulating "
    "the G1/S transition. In its active hypophosphorylated form, RB binds and inhibits E2F transcription "
    "factors in two ways: (1) by directly sequestering E2F, and (2) by recruiting histone deacetylases "
    "and methyltransferases that repress target gene promoters such as cyclin E."
)
add_body(doc,
    "Mitogenic signals → Cyclin D expression → Cyclin D-CDK4/6 formation → Phosphorylation (inactivation) "
    "of RB → Release of E2F → Transcription of cyclin E → Cyclin E-CDK2 activity → S phase entry. "
    "Once in S phase, cells are committed to divide. During M phase, phosphatases regenerate active "
    "hypophosphorylated RB. The loss of RB function (mutation, deletion, or functional inactivation by "
    "viral oncoproteins such as HPV E7) is a pivotal event in carcinogenesis."
    " (Robbins & Kumar Basic Pathology, 10th ed.)"
)

doc.add_paragraph()

# --- 3.5 p53 ---
add_section_heading(doc, "3.5  Role of p53 — Guardian of the Genome", size=12, bold=True)

add_body(doc,
    "p53 (encoded by the TP53 tumor suppressor gene) is activated in response to DNA damage, oxidative "
    "stress, hypoxia, and oncogene activation. Under normal conditions, p53 levels are kept low by MDM2 "
    "(mouse double minute 2), an E3 ubiquitin ligase that targets p53 for proteasomal degradation. "
    "DNA damage activates ATM/ATR kinases, which phosphorylate p53, dissociating it from MDM2 and allowing "
    "its accumulation."
)
add_body(doc,
    "Activated p53 functions as a transcription factor with three potential outcomes:"
)
add_bullet(doc, "Cell cycle arrest: p53 transactivates CDKN1A (encoding p21). p21 inhibits Cyclin E-CDK2 "
           "and Cyclin D-CDK4/6, preventing RB phosphorylation and arresting cells in G1. This pause "
           "allows DNA repair.")
add_bullet(doc, "DNA repair: p53 induces GADD45 and other DNA repair genes.")
add_bullet(doc, "Apoptosis/Senescence: If DNA damage is irreparable, p53 upregulates pro-apoptotic genes "
           "(BAX, PUMA, NOXA), triggering the mitochondrial apoptosis pathway. Alternatively, p53 can "
           "induce permanent senescence via changes in chromatin structure.")

add_body(doc,
    "Loss of TP53 function occurs in over 50% of all human cancers. Oral squamous cell carcinoma "
    "harbors TP53 mutations in approximately 50–70% of cases. HPV E6 oncoprotein promotes p53 "
    "ubiquitination and degradation, effectively nullifying this guardian function."
)

doc.add_paragraph()

# --- 3.6 DYSREGULATION IN CANCER ---
add_section_heading(doc, "3.6  Dysregulation of the Cell Cycle in Neoplasia", size=12, bold=True)

add_body(doc,
    "Virtually all cancers harbor genetic lesions that disable the G1/S checkpoint, causing cells to "
    "continually re-enter S phase. These fall into two major categories:"
)
add_bullet(doc, "Gain-of-function mutations: Overexpression of cyclin D1 (chromosome 11q13 amplification) "
           "or activating mutations in CDK4 → excessive CDK4/6 activity → RB hyperphosphorylation → "
           "unchecked G1/S transition. Cyclin D1 overexpression is found in mantle cell lymphoma, "
           "breast carcinoma, and a subset of oral squamous cell carcinomas.")
add_bullet(doc, "Loss-of-function mutations: Deletion or epigenetic silencing of CDKN2A (encoding p16) "
           "is one of the most common tumor suppressor alterations across all cancers, found in over "
           "50% of OSCCs. Loss of p16 removes the brake on CDK4/6, accelerating G1 progression.")
add_bullet(doc, "RB loss: Biallelic inactivation of RB (mutation, deletion, or viral oncoprotein-mediated "
           "inactivation) disables the G1/S gatekeeper.")
add_bullet(doc, "TP53 mutation: Found in 50–70% of OSCCs; allows cells with damaged DNA to bypass "
           "G1 arrest and apoptosis, accumulating further mutations.")

doc.add_paragraph()

# =====================================================================
# 4. APPLIED ASPECT (>= 2 pages)
# =====================================================================
add_section_heading(doc, "4. APPLIED ASPECT", level=1, size=13, bold=True,
                    color=(0, 70, 127), underline=True)

add_body(doc,
    "The applied significance of cell cycle biology in oral pathology is far-reaching. Understanding "
    "the molecular machinery of cell cycle regulation illuminates the pathogenesis of common oral lesions, "
    "informs histopathological interpretation, guides molecular diagnostics, and underpins targeted "
    "therapeutic strategies."
)

# --- 4.1 ---
add_section_heading(doc, "4.1  Cell Cycle and Oral Squamous Cell Carcinoma (OSCC)", size=12, bold=True)

add_body(doc,
    "Oral squamous cell carcinoma is the sixth most common cancer worldwide and accounts for over 90% "
    "of oral malignancies. The multistep carcinogenesis of OSCC involves sequential accumulation of cell "
    "cycle regulatory gene alterations:"
)
add_bullet(doc, "CDKN2A (p16) deletion/silencing: Loss of the p16 tumor suppressor is among the earliest "
           "molecular events in oral carcinogenesis. p16 normally inhibits CDK4/6, preventing RB "
           "phosphorylation and G1/S transition. Its loss allows unchecked cyclin D-CDK4/6 activity, "
           "driving cells past the G1 restriction point. CDKN2A silencing by promoter hypermethylation "
           "is detectable in oral leukoplakia — sometimes even before histological dysplasia — making "
           "it a potential early biomarker.")
add_bullet(doc, "Cyclin D1 overexpression (CCND1 amplification): The CCND1 gene, located at chromosome "
           "11q13, is amplified in approximately 30–40% of OSCCs. Overexpression of cyclin D1 drives "
           "excessive CDK4/6 activity, hyperphosphorylation of RB, and accelerated G1/S progression. "
           "Immunohistochemical detection of cyclin D1 overexpression correlates with poor prognosis "
           "and lymph node metastasis in OSCC.")
add_bullet(doc, "TP53 mutation: Mutations in TP53 are found in 50–70% of OSCCs, more common in "
           "tobacco/alcohol-related tumors than HPV-associated cancers. Loss of p53 eliminates "
           "G1 arrest in response to DNA damage, impairs DNA repair, prevents apoptosis, and allows "
           "mutated daughter cells to accumulate. p53 immunohistochemistry demonstrates diffuse nuclear "
           "positivity in dysplastic and malignant oral epithelium.")
add_bullet(doc, "RB pathway inactivation: In HPV-negative OSCC, RB gene mutation (~10%) or loss of "
           "upstream regulators (p16) effectively inactivates this pathway. In HPV-positive OSCC "
           "(particularly oropharyngeal), the E7 oncoprotein directly binds and destabilizes RB protein, "
           "releasing E2F and driving S phase entry.")
add_bullet(doc, "HPV E6/E7 oncoproteins: HPV E7 degrades RB; HPV E6 ubiquitinates and degrades p53. "
           "Together, these abolish both the RB and p53 cell cycle checkpoints, explaining the unique "
           "molecular pathogenesis of HPV-driven oropharyngeal carcinoma. HPV-positive tumors show "
           "characteristic p16 overexpression (paradoxically, due to loss of RB-mediated feedback "
           "repression on p16), which serves as a surrogate IHC marker for HPV infection.")

doc.add_paragraph()

# --- 4.2 ---
add_section_heading(doc, "4.2  Cell Cycle in Oral Epithelial Dysplasia (OED) and Premalignant Lesions", size=12, bold=True)

add_body(doc,
    "Oral epithelial dysplasia represents a histopathological spectrum of progressive architectural and "
    "cytological abnormalities that correlate with malignant transformation risk. Cell cycle alterations "
    "are progressive and grade-dependent:"
)
add_bullet(doc, "Mild dysplasia: Aberrant p53 expression and focal loss of p16 are detectable. Increased "
           "Ki-67 (a proliferation marker expressed in all active phases of the cell cycle — G1, S, G2, "
           "and M, but not G0) labelling index indicates expansion of the proliferative compartment "
           "beyond the basal layer.")
add_bullet(doc, "Moderate dysplasia: Cyclin D1 overexpression, p21 dysregulation, and further reduction "
           "in p16 expression. Abnormal mitotic figures — a histological hallmark of mitotic checkpoint "
           "failure — are seen in mid-spinous layers.")
add_bullet(doc, "Severe dysplasia / Carcinoma-in-situ: Near-complete loss of p16, diffuse p53 positivity, "
           "high Ki-67 LI throughout full epithelial thickness. These markers collectively support a "
           "diagnosis of high-grade dysplasia and predict transformation risk.")
add_bullet(doc, "Oral submucous fibrosis (OSMF): A recognized premalignant condition with progressive "
           "fibrosis driven by areca nut alkaloids (arecoline). Arecoline inhibits CDK inhibitor expression, "
           "upregulates cyclin D1, and stimulates TGF-beta-mediated fibrosis while simultaneously "
           "dysregulating epithelial cell cycle checkpoints. OSMF epithelium shows elevated Ki-67 and "
           "aberrant p53 in areas of dysplastic change, correlating with malignant transformation rates "
           "of 7–13%.")

doc.add_paragraph()

# --- 4.3 ---
add_section_heading(doc, "4.3  Odontogenic Tumors and the Cell Cycle", size=12, bold=True)

add_body(doc,
    "Cell cycle deregulation extends to odontogenic tumors and cysts. While these lesions are generally "
    "benign, their biological behavior can be understood through cell cycle analysis:"
)
add_bullet(doc, "Ameloblastoma: Shows overexpression of cyclin D1 and loss of p16. Elevated Ki-67 labelling "
           "indices (typically 5–15%) correlate with locally aggressive growth behavior. BRAF V600E mutation "
           "(present in ~50–80% of conventional ameloblastomas) activates the MAPK pathway, driving cyclin "
           "D1 expression and cell cycle entry.")
add_bullet(doc, "Odontogenic keratocyst (OKC): Exhibits markedly higher Ki-67 LI (10–40%) compared to "
           "dentigerous cysts and radicular cysts, reflecting its aggressive growth pattern and recurrence "
           "tendency. Loss of PTCH1 (Gorlin syndrome) impairs regulation of cellular proliferation through "
           "the Hedgehog pathway-cyclin D1 axis.")
add_bullet(doc, "Radicular cysts vs. Periapical granuloma: Higher Ki-67 labelling in radicular cyst "
           "epithelium vs granuloma tissue reflects active cell cycle progression driving cyst expansion.")
add_bullet(doc, "Mucoepidermoid carcinoma: MAML2 gene rearrangement activates Notch target genes and "
           "cyclin D1, driving aberrant cell cycle progression. Cyclin D1 and Ki-67 expression correlate "
           "with histological grade.")

doc.add_paragraph()

# --- 4.4 ---
add_section_heading(doc, "4.4  Ki-67 as a Clinical Proliferation Marker in Oral Pathology", size=12, bold=True)

add_body(doc,
    "Ki-67 (encoded by MKI67) is a nuclear protein expressed throughout active cell cycle phases (G1, S, G2, M) "
    "but absent in G0. Its immunohistochemical detection provides a direct readout of the proliferative "
    "fraction in a tissue section — the Ki-67 Labelling Index (LI)."
)
add_bullet(doc, "Diagnostic utility: Ki-67 LI helps differentiate reactive hyperplasia (low Ki-67, basal "
           "layer-restricted) from dysplasia (elevated Ki-67, suprabasal extension) and carcinoma "
           "(diffuse full-thickness Ki-67 positivity).")
add_bullet(doc, "Prognostic value in OSCC: High Ki-67 LI (>50%) correlates with increased lymph node "
           "metastasis, local recurrence, and reduced overall survival.")
add_bullet(doc, "AgNOR (Argyrophilic Nucleolar Organiser Regions): AgNOR staining reflects rRNA gene "
           "transcriptional activity, which parallels cell cycle activity. Increased mean AgNOR count "
           "per nucleus is observed in high-grade dysplasia and carcinoma.")
add_bullet(doc, "PCNA (Proliferating Cell Nuclear Antigen): A cofactor for DNA polymerase delta, expressed "
           "during S phase. Used as an older proliferation marker; less specific than Ki-67 due to its "
           "extended half-life after cell cycle exit.")

doc.add_paragraph()

# --- 4.5 ---
add_section_heading(doc, "4.5  Cell Cycle Targets in Oral Cancer Therapy", size=12, bold=True)

add_body(doc,
    "The cell cycle provides multiple actionable therapeutic targets in oral cancer:"
)
add_bullet(doc, "CDK4/6 inhibitors (Palbociclib, Ribociclib, Abemaciclib): These drugs block cyclin D-CDK4/6 "
           "complexes, preventing RB phosphorylation and arresting cells in G1. They are FDA-approved for "
           "HR+/HER2- breast cancer and are under investigation for OSCC, particularly in tumors with cyclin "
           "D1 amplification. Recent Phase II data suggest activity in CCND1-amplified head and neck "
           "squamous cell carcinoma.")
add_bullet(doc, "WEE1/CHK1 inhibitors: WEE1 kinase phosphorylates and inhibits CDK1, enforcing the G2/M "
           "checkpoint. WEE1 inhibition (AZD1775/Adavosertib) forces G2 checkpoint-deficient cells "
           "(often TP53-mutant) into premature mitosis with unrepaired DNA, causing mitotic catastrophe. "
           "Rational combination with DNA-damaging chemotherapy or radiation is being explored in OSCC.")
add_bullet(doc, "PARP inhibitors: Exploit synthetic lethality in homologous recombination-deficient tumors; "
           "relevant to OSCC with BRCA pathway alterations.")
add_bullet(doc, "p53-directed therapy: APR-246 (Eprenetapopt) reactivates mutant p53, restoring its "
           "ability to arrest the cell cycle and induce apoptosis. Under clinical investigation for "
           "TP53-mutant head and neck cancers.")
add_bullet(doc, "Radiotherapy and cell cycle: Radiation sensitivity is phase-dependent — M and late G2 "
           "are most radiosensitive; late S phase is most resistant. This forms the biological rationale "
           "for fractionated radiotherapy, which allows redistribution of cells into sensitive phases "
           "between fractions.")
add_bullet(doc, "Chemotherapy: Most conventional cytotoxic agents (5-FU, cisplatin, taxanes) exploit cell "
           "cycle phase specificity. Taxanes stabilize microtubules, preventing spindle assembly and "
           "triggering the spindle assembly checkpoint, leading to mitotic arrest and apoptosis.")

doc.add_paragraph()

# --- 4.6 ---
add_section_heading(doc, "4.6  Cell Cycle Markers in Oral Cancer Screening and Diagnosis", size=12, bold=True)

add_body(doc,
    "Emerging molecular diagnostic approaches leverage cell cycle biomarkers for early detection and "
    "risk stratification:"
)
add_bullet(doc, "Salivary biomarkers: Cell cycle-related non-coding RNAs (ncRNAs), including miR-21, "
           "miR-31, and specific lncRNAs, are detectable in saliva and blood of OSCC patients. "
           "(Kalmatte A, Rekha PD, Ratnacaram CK. Mol Biol Rep. 2023 Nov; PMID: 37717257)")
add_bullet(doc, "DNA ploidy analysis: Flow cytometry and image analysis of exfoliated cells or biopsy "
           "specimens measures DNA content. Aneuploidy — reflecting spindle checkpoint failure — "
           "correlates with dysplasia grade and malignant transformation risk in oral leukoplakia.")
add_bullet(doc, "Loss of heterozygosity (LOH) at 9p21 (CDKN2A locus) and 17p13 (TP53 locus): Detectable "
           "by PCR-based analysis of brush biopsy specimens or saliva; predicts transformation risk in "
           "oral potentially malignant disorders.")
add_bullet(doc, "IHC panel in oral pathology practice: A standardized panel of p53 (tumor suppressor), "
           "p16 (CDK inhibitor/HPV surrogate), cyclin D1 (CDK activator), and Ki-67 (proliferation index) "
           "provides comprehensive cell cycle status assessment in challenging biopsy specimens.")

doc.add_paragraph()

# =====================================================================
# 5. CONCLUSION
# =====================================================================
add_section_heading(doc, "5. CONCLUSION", level=1, size=13, bold=True,
                    color=(0, 70, 127), underline=True)

add_body(doc,
    "The cell cycle is a precisely orchestrated molecular program that governs cellular proliferation, "
    "growth arrest, DNA repair, and apoptosis. Its four phases — G1, S, G2, and M — are driven by "
    "cyclin/CDK complexes, regulated by CDK inhibitors, and safeguarded by checkpoint surveillance "
    "mechanisms centered on p53 and RB. Aberrations in this machinery — whether through oncogene "
    "activation (cyclin D1 overexpression, CDK4 amplification), tumor suppressor loss (p16/CDKN2A, "
    "RB, TP53), or viral oncoprotein action (HPV E6/E7) — are the molecular foundation of oral "
    "carcinogenesis."
)
add_body(doc,
    "For the oral pathologist, cell cycle biology is not merely an academic exercise but a practical "
    "framework for understanding the histopathological spectrum from reactive hyperplasia to invasive "
    "carcinoma. Immunohistochemical markers of cell cycle activity (Ki-67, p53, p16, cyclin D1) are "
    "now routine tools in oral pathology diagnosis and prognostication. Looking forward, targeted "
    "therapeutics directed at cell cycle kinases (CDK4/6 inhibitors, WEE1 inhibitors) represent "
    "a precision oncology approach that promises improved outcomes for patients with oral cancer. "
    "A thorough grasp of cell cycle regulation is therefore indispensable for the practice of "
    "modern oral pathology and oral medicine."
)

doc.add_paragraph()

# =====================================================================
# 6. REFERENCES
# =====================================================================
add_section_heading(doc, "6. REFERENCES", level=1, size=13, bold=True,
                    color=(0, 70, 127), underline=True)

references = [
    "Kumar V, Abbas AK, Aster JC. Robbins & Kumar Basic Pathology. 10th ed. Philadelphia: Elsevier; 2023. Chapter 6: Neoplasia — Control of the Cell Cycle, pp. 231–237.",
    "Kumar V, Abbas AK, Aster JC, Deyrup AT. Robbins, Cotran & Kumar Pathologic Basis of Disease. 10th ed. Philadelphia: Elsevier; 2025. Chapter 1: The Cell as a Unit of Health and Disease, pp. 38–42.",
    "Ross MH, Pawlina W. Histology: A Text and Atlas with Correlated Cell and Molecular Biology. 9th ed. Philadelphia: Wolters Kluwer; 2024. Chapter 3: Cell Cycle, pp. 291–292.",
    "Neville BW, Damm DD, Allen CM, Chi AC. Oral and Maxillofacial Pathology. 4th ed. St. Louis: Elsevier; 2016. Chapter 13: Epithelial Pathology.",
    "Regezi JA, Sciubba JJ, Jordan RCK. Oral Pathology: Clinical Pathologic Correlations. 7th ed. St. Louis: Elsevier; 2017. Chapter 8: Premalignant Lesions.",
    "Sapp JP, Eversole LR, Wysocki G. Contemporary Oral and Maxillofacial Pathology. 2nd ed. St. Louis: Mosby; 2004.",
    "Scully C. Oral and Maxillofacial Medicine: The Basis of Diagnosis and Treatment. 3rd ed. Edinburgh: Churchill Livingstone; 2013.",
    "Sherr CJ. Cancer cell cycles. Science. 1996;274(5293):1672–1677. PMID: 8939849.",
    "Kalmatte A, Rekha PD, Ratnacaram CK. Emerging cell cycle related non-coding RNA biomarkers from saliva and blood for oral squamous cell carcinoma. Mol Biol Rep. 2023;50(11):9437–9447. PMID: 37717257.",
    "Hanna R, Rebaudi AL, Warnakulasuriya S. Immunological Analysis of Oral Cytobrush Specimens for Early Detection of Oral Cancer Biomarkers: A Comprehensive Review. Int J Mol Sci. 2026;27(4):1781. PMID: 41752195.",
    "Williams GH, Stoeber K. The cell cycle and cancer. J Pathol. 2012;226(2):352–364. PMID: 21990158.",
    "Hanahan D, Weinberg RA. Hallmarks of cancer: the next generation. Cell. 2011;144(5):646–674. PMID: 21376230.",
    "Shah JP, Patel SG, Singh B (eds). Jatin Shah's Head and Neck Surgery and Oncology. 4th ed. Philadelphia: Elsevier; 2012.",
    "Cummings CW. Cummings Otolaryngology: Head and Neck Surgery. 7th ed. Philadelphia: Elsevier; 2021.",
]

for i, ref in enumerate(references, start=1):
    para = doc.add_paragraph()
    run_num = para.add_run(f"{i}.  ")
    run_num.bold = True
    run_num.font.name = 'Times New Roman'
    run_num.font.size = Pt(11)
    run_ref = para.add_run(ref)
    run_ref.font.name = 'Times New Roman'
    run_ref.font.size = Pt(11)
    para.paragraph_format.space_after = Pt(4)
    para.paragraph_format.left_indent = Inches(0.3)
    para.paragraph_format.first_line_indent = Inches(-0.3)

# =====================================================================
# SAVE
# =====================================================================
output_path = "/tmp/workspace/cell-cycle-mds/Cell_Cycle_MDS_OralPathology.docx"
doc.save(output_path)
print(f"Document saved: {output_path}")