Neoplasia Practice Questions

Q: Which of the following is a metastasis suppressor gene in relation to prostate cancer?

KAI-1. **Explanation:** Metastasis suppressor genes are a distinct class of genes that inhibit the spread of cancer cells without necessarily affecting the growth of the primary tumor. **A. KAI-1 (CD82):** This is the correct answer. Located on chromosome 11p11.2, KAI-1 encodes a cell surface glycoprotein (tetraspanin) that promotes cell-cell adhesion and suppresses tumor cell migration. Its expression is significantly downregulated during the progression of **prostate cancer**, making it a specific marker for metastatic potential in this malignancy. **B. NM 23:** While this was the first metastasis suppressor gene discovered, it is most classically associated with **breast cancer** and melanomas. It functions as a nucleoside diphosphate kinase. **C. KISS-1:** This gene encodes the protein kisspeptin. It acts as a metastasis suppressor primarily in **melanoma** and breast cancer by signaling through G-protein coupled receptors to inhibit chemotaxis and invasion. **D. p53:** This is a classic **Tumor Suppressor Gene** (the "Guardian of the Genome"). While its loss certainly leads to advanced cancer and eventual metastasis, it primarily functions by regulating the cell cycle, DNA repair, and apoptosis at the primary site, rather than being classified specifically as a "metastasis suppressor gene." **High-Yield Clinical Pearls for NEET-PG:** * **KAI-1** = Prostate Cancer. * **NM 23** = Breast Cancer. * **BRMS1** = Breast Cancer Metastasis Suppressor. * **MKK4** = Ovarian Cancer. * **E-Cadherin** loss is a hallmark of the Epithelial-Mesenchymal Transition (EMT), a critical step in the metastatic cascade.

Q: N-MYC amplification is associated with which of the following conditions?

Neuroblastoma. **Explanation:** The **MYC family of proto-oncogenes** (C-MYC, N-MYC, and L-MYC) encodes transcription factors that play a pivotal role in cell growth and proliferation. **N-MYC amplification** is a classic example of gene amplification in human tumors, where the gene is replicated many times, appearing as "Double Minutes" (extrachromosomal fragments) or "Homogeneously Staining Regions" (HSRs) on karyotyping. **Why Neuroblastoma is correct:** N-MYC amplification occurs in approximately 25–30% of **Neuroblastomas** [1]. It is the most significant prognostic indicator for this childhood tumor; its presence signifies an aggressive clinical course, rapid tumor progression, and a poor prognosis, regardless of the clinical stage [1]. **Analysis of Incorrect Options:** * **A. Burkitt Lymphoma:** This is associated with the **translocation t(8;14)**, which leads to the overexpression of **C-MYC**, not N-MYC [2]. * **B. Squamous Cell Carcinoma of the Lung:** While various mutations occur, **L-MYC** amplification is more specifically associated with Small Cell Carcinoma of the lung. * **C. Astrocytoma:** High-grade gliomas (like Glioblastoma) are more commonly associated with **EGFR amplification** or PTEN mutations rather than N-MYC. **High-Yield Clinical Pearls for NEET-PG:** * **C-MYC:** Burkitt Lymphoma (t(8;14)) [2]. * **N-MYC:** Neuroblastoma (Poor prognosis) [1]. * **L-MYC:** Small Cell Carcinoma of the Lung. * **Double Minutes/HSRs:** These are the cytogenetic hallmarks of gene amplification (commonly seen with N-MYC in Neuroblastoma and ERBB2 in Breast Cancer). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 486-487. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 324-325.

Q: The Ames test is a method for detecting which of the following?

Mutagenesis in bacteria. **Explanation:** The **Ames Test** is a rapid, high-throughput screening method used to determine the **mutagenic potential** of chemical compounds. It is based on the principle that most carcinogens are also mutagens [1]. **Why Option D is Correct:** The test utilizes a specific strain of **Salmonella typhimurium** that carries a mutation in the gene responsible for synthesizing the amino acid **histidine** (histidine auxotrophs). These bacteria cannot grow on a histidine-deficient medium. When a test chemical is added, if it is mutagenic, it induces a "back mutation" (reversion) that restores the bacteria's ability to synthesize histidine, allowing them to grow. A significant increase in colonies compared to the control indicates that the substance is a mutagen. **Why Other Options are Incorrect:** * **Options A & B:** While the Ames test is used to *screen* for potential carcinogens, it does not directly measure carcinogenesis (the formation of cancer) in rodents or primates [1]. Those require long-term, expensive *in vivo* animal bioassays. * **Option C:** Teratogenesis refers to the induction of structural defects in a fetus. The Ames test measures genetic mutations in prokaryotic cells, not developmental toxicity in mammalian embryos. **High-Yield Clinical Pearls for NEET-PG:** * **S9 Mix:** Since some chemicals only become mutagenic after being metabolized by the liver, **rat liver extract (S9 fraction)** is added to the Ames test to simulate mammalian metabolic activation. * **Correlation:** Approximately **90%** of known carcinogens test positive in the Ames test [1]. * **Other Genotoxicity Tests:** Sister Chromatid Exchange (SCE) and the Micronucleus test are used to detect chromosomal damage in mammalian cells. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 330-332.

Question 1

What is the most successful application of tumor markers?

Accepted Answer

Monitoring the effect of treatment and early detection of recurrence

Answer

Screening in asymptomatic individuals

Answer

Differentiating benign from malignant lesions

Answer

Staging the extent of disease

Question 2

The APC gene exerts its effect in combination with which of the following?

Accepted Answer

Beta-catenin

Answer

E-cadherin

Answer

Alpha-catenin

Answer

BCAP31

Question 3

Which of the following is a metastasis suppressor gene in relation to prostate cancer?

Accepted Answer

KAI-1

Answer

NM 23

Answer

KISS

Answer

p53

Question 4

N-MYC amplification is associated with which of the following conditions?

Accepted Answer

Neuroblastoma

Answer

Burkitt lymphoma

Answer

Squamous cell carcinoma of the lung

Answer

Astrocytoma

Question 5

Reversible loss of polarity with abnormality in size and shape of cells is known as?

Accepted Answer

Dysplasia

Answer

Metaplasia

Answer

Hyperplasia

Answer

Anaplasia

Question 6

The Ames test is a method for detecting which of the following?

Accepted Answer

Mutagenesis in bacteria

Answer

Carcinogenesis in rodents

Answer

Carcinogenesis in primates

Answer

Teratogenesis in any mammalian species

Question 7

With reference to neoplasia, what does the term 'tumor progression' mean?

Accepted Answer

Sequential appearance of features of increasing malignancy

Answer

Spread of cancer to distant sites

Answer

Rate of growth of tumors

Answer

Ability of cancer cells to resemble their normal counterparts

Question 8

Cushing syndrome as a paraneoplastic syndrome is seen with all of the following malignancies EXCEPT:

Accepted Answer

Papillary carcinoma thyroid

Answer

Bronchial carcinoid

Answer

Thymus carcinoid

Answer

Medullary carcinoma thyroid

Question 9

What is the most common inherited childhood tumor?

Accepted Answer

Retinoblastoma

Answer

Leukemia

Answer

Neuroblastoma

Answer

Wilms tumor

Question 10

Which of the following is essential for tumor metastasis?

Accepted Answer

Angiogenesis

Answer

Tumorogenesis

Answer

Apoptosis

Answer

Inhibition of Tyrosine kinase activity

Neoplasia — MCQs

Neoplasia — MCQs

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