Neoplasia Practice Questions

Q: A researcher is studying a cell line that shows resistance to apoptosis despite DNA damage. Analysis reveals overexpression of a protein that normally prevents p53 from inducing cell cycle arrest. Which protein is most likely overexpressed?

MDM2. ***MDM2*** - **MDM2** functions as an **E3 ubiquitin ligase** that directly binds to **p53**, promoting its degradation and inhibiting its transcriptional activity. - Overexpression leads to the loss of **p53-mediated cell cycle arrest** (via p21) and apoptosis, allowing cells with **DNA damage** to survive and proliferate. *Caspase-3* - **Caspase-3** is an **executioner caspase** that plays a central role in the final stages of the apoptotic cascade, not the regulation of p53. - Overexpression would typically **promote apoptosis** rather than providing resistance to it after DNA damage. *Cytochrome C* - **Cytochrome C** is released from the **mitochondria** into the cytosol to activate the **apoptosome** during the intrinsic pathway of apoptosis. - Its release occurs **downstream** of p53 activation and is not a protein that inhibits p53-induced cell cycle arrest. *Bcl-2* - **Bcl-2** is an **anti-apoptotic** protein that prevents the release of Cytochrome C, but it does not directly regulate p53-mediated **cell cycle arrest**. - While its overexpression prevents apoptosis, the specific mechanism of inhibiting **p53's ability to induce arrest** points towards MDM2.

Q: Which carbohydrate tumor marker is associated with breast cancer?

CA 15-3. **Explanation:** **CA 15-3 (Cancer Antigen 15-3)** is the correct answer. It is a carbohydrate antigen derived from the **MUC1 gene** product. In clinical practice, it is primarily used as a tumor marker for **breast cancer**. While it is not sensitive enough for screening early-stage disease, it is highly valuable for monitoring treatment response and detecting the recurrence or metastasis of breast malignancy. **Analysis of Incorrect Options:** * **CA 125:** This is the classic marker for **Ovarian Cancer** (specifically non-mucinous epithelial tumors). It can also be elevated in endometriosis, pelvic inflammatory disease, and pregnancy. * **CA 34:** This is not a standard clinical tumor marker used in the NEET-PG curriculum. It is likely a distractor. (Note: CD34 is a marker for hematopoietic stem cells and vascular endothelium). * **CA 19-9:** This is the primary marker for **Pancreatic Cancer** and cholangiocarcinoma. It is also associated with other gastrointestinal malignancies and obstructive jaundice. **High-Yield Clinical Pearls for NEET-PG:** * **CA 27-29:** Another marker frequently associated with breast cancer, often used interchangeably with CA 15-3. * **CEA (Carcinoembryonic Antigen):** While most famous for colorectal cancer, it is the second most common marker used to monitor breast cancer. * **HER2/neu:** A proto-oncogene (not a carbohydrate marker) used to determine prognosis and eligibility for Trastuzumab therapy in breast cancer patients. * **AFP (Alpha-fetoprotein):** Marker for Hepatocellular Carcinoma (HCC) and Yolk Sac Tumors. * **PSA (Prostate Specific Antigen):** Marker for Prostate Cancer.

Q: Alpha-fetoprotein is increased in which of the following conditions?

Hepatoblastoma. **Explanation:** Alpha-fetoprotein (AFP) is a glycoprotein normally produced by the fetal yolk sac and liver. In clinical practice, it serves as a crucial tumor marker for specific malignancies derived from these tissues. **Why Hepatoblastoma is correct:** Hepatoblastoma is the most common primary liver tumor in children. Since it originates from primitive hepatic precursor cells, it characteristically secretes very high levels of AFP (elevated in >90% of cases). It is used for both diagnosis and monitoring treatment response. **Analysis of Incorrect Options:** * **Neuroblastoma:** This is a neural crest-derived tumor. The relevant markers here are urinary catecholamines (VMA and HVA), not AFP. * **Seminoma:** Pure seminomas are notorious for **not** producing AFP. If AFP is elevated in a suspected seminoma, it indicates the presence of a non-seminomatous component (like a yolk sac tumor), changing the diagnosis to a Mixed Germ Cell Tumor. (Note: Seminomas may occasionally show mild elevations in hCG). * **Renal Cell Carcinoma (RCC):** RCC does not typically produce AFP. Common associations include paraneoplastic syndromes (erythropoietin, PTHrP), but not fetal proteins. **High-Yield Clinical Pearls for NEET-PG:** * **AFP is elevated in:** Hepatocellular Carcinoma (HCC), Hepatoblastoma, and Non-Seminomatous Germ Cell Tumors (specifically **Yolk Sac Tumors/Endodermal Sinus Tumors**). * **Neural Tube Defects:** Maternal serum AFP is elevated in Spina Bifida and Anencephaly, but decreased in Down Syndrome. * **Rule of Thumb:** In testicular tumors, **AFP elevation always rules out a pure seminoma.** * **Yolk Sac Tumor:** This is the most common testicular tumor in infants and children, characterized by Schiller-Duval bodies and high AFP.

Q: Which of the following conditions is inherited in an autosomal dominant pattern?

Retinoblastoma. **Explanation:** The correct answer is **Retinoblastoma (Option A)**. Retinoblastoma is the most common primary intraocular malignancy of childhood. While 60% of cases are sporadic and unilateral, 40% are hereditary. Hereditary retinoblastoma follows an **Autosomal Dominant** inheritance pattern with high penetrance (90%). It is caused by a mutation in the **RB1 gene** located on chromosome **13q14**. According to **Knudson’s Two-Hit Hypothesis**, in hereditary cases, the first mutation (hit) is germline (inherited), and the second is somatic. This explains why hereditary cases are often bilateral, multifocal, and present at an earlier age. **Why the other options are incorrect:** * **Ataxia Telangiectasia (Option B):** This is an **Autosomal Recessive** multisystem disorder characterized by cerebellar ataxia, oculocutaneous telangiectasia, and immunodeficiency. It involves a defect in the ATM gene (DNA repair). * **Bloom’s Syndrome (Option C):** This is an **Autosomal Recessive** disorder characterized by short stature, photosensitivity, and genomic instability due to mutations in the BLM gene. * **Xeroderma Pigmentosa (Option D):** This is an **Autosomal Recessive** condition caused by a defect in nucleotide excision repair, leading to extreme sensitivity to UV light and a high risk of skin malignancies. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presenting sign:** Leukocoria (White pupillary reflex). * **Second most common sign:** Strabismus. * **Pathognomonic Histology:** Flexner-Wintersteiner rosettes. * **Calcification:** Present in 90% of cases (visible on CT/Ultrasound B-scan); a key diagnostic feature. * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pinealoblastoma.

Question 1

A researcher is studying a cell line that shows resistance to apoptosis despite DNA damage. Analysis reveals overexpression of a protein that normally prevents p53 from inducing cell cycle arrest. Which protein is most likely overexpressed?

Accepted Answer

MDM2

Answer

Caspase-3

Answer

Cytochrome C

Answer

Bcl-2

Question 2

Which of the following statements is false regarding the role of HPV in oncogenesis?

Accepted Answer

Inactivates cyclins

Answer

Expresses oncogenic proteins

Answer

Inactivates tumor suppressors

Answer

Inhibits apoptosis

Question 3

Which carbohydrate tumor marker is associated with breast cancer?

Accepted Answer

CA 15-3

Answer

CA 125

Answer

CA 34

Answer

CA 19-9

Question 4

Which of the following is not an estrogen-dependent carcinoma?

Accepted Answer

Follicular carcinoma of the thyroid

Answer

Lobular carcinoma of the breast

Answer

Endometrial leiomyosarcoma

Answer

Carcinoma of the prostate

Question 5

What is the primary function of the p53 protein, often referred to as the 'guardian of the genome'?

Accepted Answer

Reduction of cell mutation rate

Answer

Increase in cell proliferation

Answer

Evasion of apoptosis

Answer

Induction of necrosis

Question 6

Alpha-fetoprotein is increased in which of the following conditions?

Accepted Answer

Hepatoblastoma

Answer

Neuroblastoma

Answer

Seminoma

Answer

Renal cell carcinoma

Question 7

Which of the following is NOT a recognized use of tumor markers?

Accepted Answer

Confirming the diagnosis of a cancer.

Answer

Screening for cancer in asymptomatic individuals.

Answer

Monitoring a cancer patient for recurrence.

Answer

Assessing the response to treatment in a cancer patient.

Question 8

What is the inheritance pattern of familial retinoblastomas?

Accepted Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

X-linked dominant

Answer

X-linked recessive

Question 9

Tumour cells avoid immunogenic response by all except:

Accepted Answer

Decreased expression of MHC II molecule

Answer

Decreased expression of MHC I molecule

Answer

Immunosuppression

Answer

Antigen loss

Question 10

Which of the following conditions is inherited in an autosomal dominant pattern?

Accepted Answer

Retinoblastoma

Answer

Ataxia telangiectasia

Answer

Bloom's syndrome

Answer

Xeroderma pigmentosa

Neoplasia — MCQs

Neoplasia — MCQs

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