OCN Cancer Biology and Pathophysiology 2 — Questions and Answers
Question 1: TNM staging for solid tumors classifies cancers based on which three factors?
- Tumor size/extent, lymph Node involvement, and Metastasis (Correct answer)
- Tumor type, Necrosis, and Molecular markers
- Treatment response, Nodular pattern, and Metastasis
- Tissue grade, Necrosis, and Margin status
Correct answer: Tumor size/extent, lymph Node involvement, and Metastasis
TNM staging uses primary tumor extent (T), regional lymph node involvement (N), and distant metastasis (M) to classify cancer stage and guide treatment.
Question 2: Which oncogene is frequently amplified in HER2-positive breast cancer, making it a therapeutic target?
- ERBB2 (HER2/neu) (Correct answer)
- KRAS
- MYC
- BCL-2
Correct answer: ERBB2 (HER2/neu)
ERBB2 gene amplification produces excess HER2 protein on the cell surface, driving uncontrolled cell proliferation in HER2-positive breast cancer.
Question 3: Tumor grade refers to which pathological characteristic?
- How differentiated (similar to normal tissue) the cancer cells appear under microscopy (Correct answer)
- The physical size of the tumor
- The number of lymph nodes involved
- The presence of distant metastases
Correct answer: How differentiated (similar to normal tissue) the cancer cells appear under microscopy
Tumor grade reflects the degree of cellular differentiation: low grade (well differentiated) cells look like normal cells, while high grade (poorly differentiated) cells are more abnormal and aggressive.
Question 4: Lynch syndrome (hereditary non-polyposis colorectal cancer) is caused by mutations in which genes?
- Mismatch repair genes (MLH1, MSH2, MSH6, PMS2) (Correct answer)
- BRCA1 and BRCA2
- APC and PTEN
- RB1 and TP53
Correct answer: Mismatch repair genes (MLH1, MSH2, MSH6, PMS2)
Lynch syndrome is caused by germline mutations in DNA mismatch repair genes, leading to microsatellite instability and increased risk of colorectal, endometrial, and other cancers.
Question 5: Which tumor marker is most specific for monitoring colorectal cancer recurrence?
- Carcinoembryonic antigen (CEA) (Correct answer)
- CA-125
- Alpha-fetoprotein (AFP)
- PSA
Correct answer: Carcinoembryonic antigen (CEA)
CEA is the most widely used tumor marker for monitoring colorectal cancer response to treatment and surveillance for recurrence after resection.
Question 6: Tumor heterogeneity refers to which biological characteristic of cancers?
- Genetic diversity among cells within the same tumor, leading to varied drug sensitivities (Correct answer)
- Uniform cell populations within a tumor
- The spread of cancer to multiple organs
- Identical genetic profiles across primary and metastatic sites
Correct answer: Genetic diversity among cells within the same tumor, leading to varied drug sensitivities
Tumor heterogeneity means different cells within one tumor have different mutations, making some subpopulations resistant to specific treatments.
OCN Cancer Biology and Pathophysiology 2
TNM staging for solid tumors classifies cancers based on which three factors?