Oncopathology And Genetic Disorders End Sem Cat

## SECTION A: MBPA 3412 (ONCOPATHOLOGY) ### Question 1: Define the following terms (5 Marks) **a. Pleomorphism** Variation in size and shape of cells and their nuclei within a tumor. It is a characteristic feature of malignant neoplasms indicating lack of uniformity. **b. Anaplasia** Lack of cellular differentiation in malignant tumors. Cells lose their specialized features and resemble primitive cells with marked pleomorphism, abnormal nuclei, increased mitoses, and high nuclear-to-cytoplasmic ratio. **c. Dysplasia** Disordered growth with abnormal cells showing loss of uniformity and architectural orientation. It is a precancerous condition confined within epithelium without basement membrane invasion. Classified as mild, moderate, or severe. **d. Oncogenes** Mutated or overexpressed genes that promote cancer development. Derived from normal proto-oncogenes that regulate cell growth. Examples include RAS, MYC, and HER2. Act dominantly requiring only one mutated allele. **e. Differentiation** The extent to which tumor cells resemble their normal counterparts morphologically and functionally. Well-differentiated tumors resemble normal tissue with better prognosis; poorly differentiated tumors show little resemblance with worse prognosis. --- ### Question 2: Discuss the grading and staging of tumours (20 Marks) **INTRODUCTION** Grading and staging are two essential systems for assessing tumors. Grading evaluates microscopic features and biological behavior, while staging determines anatomical extent of disease. Both are crucial for treatment planning and prognosis. **TUMOR GRADING** Grading is based on cytologic differentiation and mitotic activity, assessing how closely tumor cells resemble normal cells. **Principles of Grading:** - Evaluates degree of differentiation - Assesses number of mitoses - Examines nuclear pleomorphism - Looks at architectural patterns **Grading Systems:** *Universal System:* - Grade I (G1): Well-differentiated, resembles normal tissue - Grade II (G2): Moderately differentiated, intermediate features - Grade III (G3): Poorly differentiated, little resemblance to normal - Grade IV (G4): Undifferentiated/anaplastic, no resemblance to normal *Specific Grading Systems:* - Gleason score for prostate cancer (scores 2-10) - Nottingham system for breast cancer (scores 3-9) - Fuhrman grade for renal cell carcinoma (grades 1-4) **Significance:** - Higher grade indicates more aggressive behavior - Correlates with prognosis and survival - Guides treatment intensity - Well-differentiated tumors have better outcomes **TUMOR STAGING** Staging determines anatomical extent of tumor spread. The most widely used system is the TNM classification. **TNM Classification:** *T (Primary Tumor):* - TX: Primary tumor cannot be assessed - T0: No evidence of primary tumor - Tis: Carcinoma in situ - T1-T4: Increasing size and local extent of primary tumor *N (Regional Lymph Nodes):* - NX: Nodes cannot be assessed - N0: No regional lymph node metastasis - N1-N3: Increasing involvement of regional lymph nodes *M (Distant Metastasis):* - M0: No distant metastasis - M1: Distant metastasis present **Stage Groupings:** After TNM assessment, tumors are assigned overall stages: - Stage 0: Carcinoma in situ - Stage I: Localized tumor, small size - Stage II: Larger tumor or limited local spread - Stage III: Extensive local and regional spread - Stage IV: Distant metastasis present **Other Staging Systems:** - FIGO staging for gynecologic cancers - Ann Arbor staging for lymphomas - Clark and Breslow for melanomas - Dukes staging for colorectal cancer **Clinical vs Pathological Staging:** - Clinical staging (cTNM): Based on physical examination, imaging, and biopsies before treatment - Pathological staging (pTNM): Based on surgical specimens and pathological examination, more accurate **Significance of Staging:** - Most important prognostic factor - Determines treatment protocols - Essential for comparing treatment outcomes - Allows standardized communication between clinicians - Stage I has best prognosis; Stage IV has worst - Guides surveillance strategies **COMPARISON: GRADING VS STAGING** **COMBINED SIGNIFICANCE** Both grading and staging together provide comprehensive tumor assessment. A high-grade, early-stage tumor may behave differently from a low-grade, advanced-stage tumor. Treatment decisions consider both parameters. **CONCLUSION** Grading and staging are complementary systems essential for cancer management. Staging provides the anatomical roadmap of disease extent and is the primary determinant of prognosis, while grading offers insight into tumor biology and aggressiveness. Together, they guide treatment selection, predict outcomes, and facilitate clinical research. --- ## SECTION B: MBPA 3413 (GENETIC DISORDERS) ### Question 1: Define the following terms (5 Marks) **a. Genetic** Refers to conditions or traits that are inherited through genes p