Neoplasia Practice Questions

Q: Spontaneous regression, though rare, is seen in which of the following conditions?

Neuroblastoma. **Explanation:** **Neuroblastoma** is a classic example of a tumor that can undergo **spontaneous regression** [1] or spontaneous maturation into a benign form (ganglioneuroma) [1]. This phenomenon is most frequently observed in **Stage 4S** (S for Special), which occurs in infants under one year of age. Despite widespread dissemination to the liver, skin, and bone marrow, these tumors often regress with minimal or no treatment due to mechanisms like cellular apoptosis or differentiation. **Analysis of Options:** * **Burkitt’s Lymphoma (A):** This is one of the fastest-growing human tumors with a very high proliferation index (Ki-67 near 100%). It is highly aggressive and requires intensive chemotherapy; it does not regress spontaneously. * **Wilms Tumor (B):** While it is a common pediatric renal tumor, it typically requires surgical resection and chemotherapy. Spontaneous regression is not a recognized feature. * **Melanoma (D):** Although rare instances of partial regression (often immune-mediated) are documented in melanoma, **Neuroblastoma** is the classic, high-yield textbook answer for spontaneous regression in the context of pediatric pathology and NEET-PG. **High-Yield Clinical Pearls for NEET-PG:** * **Neuroblastoma:** Derived from **neural crest cells** [1]. Most common extracranial solid tumor of childhood. * **Markers:** Elevated urinary catecholamines (VMA and HVA) [1]. * **Genetics:** **N-myc amplification** is the most important poor prognostic indicator [1]. * **Homer-Wright Rosettes:** Characteristic histological finding (also seen in Medulloblastoma and Retinoblastoma) [1]. * **Other tumors showing regression:** Choriocarcinoma and Renal Cell Carcinoma (rarely). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 483-487.

Q: What is the most common abnormality of a proto-oncogene in human tumors?

Point mutation in RAS family gene. ### Explanation The correct answer is **Point mutation in RAS family gene**. **1. Why RAS is correct:** The **RAS gene family** (HRAS, KRAS, NRAS) represents the most frequently mutated group of **proto-oncogenes** in human cancers. Approximately 30% of all human tumors harbor a RAS mutation. The underlying mechanism is a **single nucleotide point mutation**, most commonly at codons 12, 13, or 61. This mutation interferes with the GTPase activity of the RAS protein, trapping it in a "constitutively active" GTP-bound state, leading to continuous pro-growth signaling to the nucleus [2]. **2. Analysis of Incorrect Options:** * **p53 point mutations:** While *TP53* is the most commonly mutated gene in human cancer overall, it is a **tumor suppressor gene**, not a proto-oncogene [2]. The question specifically asks for a proto-oncogene. * **Point mutation in C-kit:** While mutations in *c-KIT* are characteristic of Gastrointestinal Stromal Tumors (GIST) and mastocytosis, they are not as ubiquitous across all human cancers as RAS mutations. * **Overexpression of RET:** *RET* mutations/rearrangements are specific to conditions like MEN 2A/2B and Medullary Thyroid Carcinoma [1]. It is a tissue-specific abnormality rather than the most common global proto-oncogene defect. **3. High-Yield Clinical Pearls for NEET-PG:** * **KRAS:** Most common RAS mutation; associated with **Pancreatic adenocarcinoma** (90%+) and **Colon cancer**. * **NRAS:** Associated with **Melanomas** and Hematologic malignancies (AML). * **HRAS:** Associated with **Bladder tumors**. * **Mechanism:** RAS mutations result in the failure of **GTP hydrolysis** (loss of GAP function), keeping the molecular switch "ON." **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 292. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 291-292.

Q: Which of the following genes has been most closely associated with familial cases of ovarian cancer?

BRCA1. **Explanation:** **Correct Option: A (BRCA1)** The **BRCA1** (Breast Cancer 1) gene, located on chromosome **17q21**, is a tumor suppressor gene involved in DNA repair via homologous recombination. Mutations in BRCA1 are the most common cause of hereditary breast and ovarian cancer syndromes. Women with a BRCA1 mutation have a significantly higher lifetime risk of developing epithelial ovarian cancer (approx. 40%) compared to those with BRCA2 mutations (approx. 15%) [1]. These cancers are typically high-grade serous carcinomas. **Incorrect Options:** * **B. WT1 (Wilms Tumor 1):** Located on chromosome 11p13, this gene is primarily associated with **Wilms tumor** (nephroblastoma) in children and certain syndromes like WAGR and Denys-Drash syndrome. * **C. NF2 (Neurofibromin 2):** Located on chromosome 22q12, mutations lead to **Neurofibromatosis Type 2**, classically characterized by bilateral acoustic neuromas (vestibular schwannomas) and meningiomas. * **D. VHL (Von Hippel-Lindau):** Located on chromosome 3p25, this gene is associated with VHL syndrome, which presents with **Renal Cell Carcinoma (clear cell type)**, hemangioblastomas, and pheochromocytomas [2]. **High-Yield Clinical Pearls for NEET-PG:** * **BRCA1 vs. BRCA2:** BRCA1 is on Chromosome **17**; BRCA2 is on Chromosome **13**. * **Male Breast Cancer:** More strongly associated with **BRCA2** than BRCA1. * **Prophylaxis:** Bilateral salpingo-oophorectomy is often recommended for mutation carriers after completion of childbearing to reduce risk [1]. * **Treatment:** Ovarian cancers with BRCA mutations are particularly sensitive to **PARP inhibitors** (e.g., Olaparib) due to "synthetic lethality." **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1058-1059. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 298-300.

Question 1

A 27-year-old man with AIDS develops a reddish, slightly raised rash on his face, neck, and mouth, consistent in appearance with Kaposi's sarcoma. Microscopically, the proliferating cells in this malignancy most closely resemble which of the following?

Accepted Answer

Angiosarcoma

Answer

Carcinosarcoma

Answer

Lymphoma

Answer

Malignant fibrous histiocytoma

Question 2

Duchenne's muscular dystrophy is inherited in which pattern?

Accepted Answer

X-linked recessive

Answer

X-linked dominant

Answer

Autosomal dominant

Answer

Autosomal recessive

Question 3

Spontaneous regression, though rare, is seen in which of the following conditions?

Accepted Answer

Neuroblastoma

Answer

Burkitt's lymphoma

Answer

Wilms tumor

Answer

Melanoma

Question 4

All the following MALT lymphomas are related to a specific organism except:

Accepted Answer

MALT lymphomas of skin - Bartonella henselae

Answer

MALT lymphomas of stomach - Helicobacter pylori

Answer

MALT lymphomas of eye - Chlamydophila psittaci

Answer

MALT lymphomas of small intestine - Campylobacter jejuni

Question 5

Burkitt's lymphoma is associated with which of the following gene anomalies?

Accepted Answer

t(8:14)

Answer

t(9:22)

Answer

del. 5q

Answer

t(17:15)

Question 6

What is the most common abnormality of a proto-oncogene in human tumors?

Accepted Answer

Point mutation in RAS family gene

Answer

p53 point mutations

Answer

Point mutation in C-kit gene

Answer

Overexpression of RET proto-oncogene

Question 7

Carcinoid syndrome is due to:

Accepted Answer

Serotonin

Answer

Adrenaline

Answer

Noradrenaline

Answer

Dopamine

Question 8

Sacrococcygeal teratoma tumor cells consist of cells from which germ layer(s)?

Accepted Answer

All of the above

Answer

Ectoderm

Answer

Endoderm

Answer

Mesoderm

Question 9

Which of the following genes has been most closely associated with familial cases of ovarian cancer?

Accepted Answer

BRCA1

Answer

WT1

Answer

NF2

Answer

VHL

Question 10

Oncogenes can be best studied by which of the following methods?

Accepted Answer

Transfection

Answer

Transduction

Answer

Transformation

Answer

Conjugation

Neoplasia — MCQs

Neoplasia — MCQs

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