General Pathology Practice Questions

Q: Which of the following is a growth factor oncogene?

sis. **Explanation:** To understand oncogenes, it is essential to categorize them based on their role in the cell signaling pathway: growth factors, growth factor receptors, signal transducers, and nuclear transcription factors [2]. **Why 'sis' is correct:** The **v-sis** oncogene (derived from the Simian Sarcoma Virus) encodes a protein that is nearly identical to the **Platelet-Derived Growth Factor (PDGF-β chain)**. When this oncogene is activated, the cell overproduces PDGF, which then acts in an autocrine fashion on the cell's own PDGF receptors [1]. This continuous stimulation leads to uncontrolled cell proliferation, commonly seen in **astrocytomas** and **osteosarcomas** [1]. **Why the other options are incorrect:** * **A, B, and D (myc, fos, jun):** These are all **Nuclear Transcription Factors**. They act at the end of the signaling cascade. Once activated, they bind to DNA to initiate the transcription of genes required for the cell cycle (like Cyclin D). * **c-myc** is famously associated with Burkitt Lymphoma [t(8;14)]. * **N-myc** is associated with Neuroblastoma. * **L-myc** is associated with Small Cell Carcinoma of the Lung. **High-Yield Clinical Pearls for NEET-PG:** * **Growth Factor Oncogenes:** *sis* (PDGF-β), *int-2* (FGF) [1]. * **Growth Factor Receptor Oncogenes:** *ERBB1* (EGFR in Squamous cell CA of lung), *ERBB2/neu* (HER2 in Breast CA), *RET* (MEN 2A/2B) [1]. * **Signal Transducers:** *RAS* (GTP-binding protein; most common oncogene in human tumors), *ABL* (Tyrosine kinase; CML). * **Mnemonic for Transcription Factors:** "My Fos-Jun" (myc, fos, jun). **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. 292-293.

Q: Which syndrome is characterized by Trisomy 13?

Patau Syndrome. **Explanation:** **Patau Syndrome (Trisomy 13)** is a severe chromosomal abnormality caused by the presence of an extra copy of chromosome 13 [1]. It is the least common and most severe of the three viable autosomal trisomies. The clinical presentation is characterized by defects in the fusion of midline structures. High-yield clinical features include the "classic triad": **Microphthalmia** (small eyes), **Cleft lip/palate**, and **Polydactyly** (extra fingers/toes) [1]. Other common findings include holoprosencephaly, "rocker-bottom" feet, and cutis aplasia (localized skin defects on the scalp). **Analysis of Incorrect Options:** * **Edward Syndrome (Trisomy 18):** Characterized by "PRINCE" features: **P**rominent occiput, **R**ocker-bottom feet, **I**ntellectual disability, **N**ondisjunction, **C**lenched fists (with overlapping fingers), and **E**ars (low-set) [1]. * **Down Syndrome (Trisomy 21):** The most common autosomal trisomy [1]. Key features include flat facies, epicanthal folds, Simian crease, and an increased risk of Alzheimer’s disease and ALL/AML. * **Turner Syndrome (45, XO):** A sex chromosome monosomy (not a trisomy). It presents in females with short stature, webbed neck, streak ovaries, and coarctation of the aorta. **NEET-PG High-Yield Pearls:** 1. **Maternal Age:** The risk for all three autosomal trisomies (13, 18, 21) increases with advanced maternal age due to meiotic nondisjunction. 2. **Survival:** Most infants with Patau Syndrome die within the first few days or months of life; survival beyond one year is rare (<10%) [1]. 3. **First Trimester Screening:** Patau syndrome typically shows decreased serum β-hCG and decreased PAPP-A. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 171-172.

Q: Pyrimidine dimers are a characteristic feature in which condition?

Xeroderma pigmentosum. Explanation: 1. Why Xeroderma Pigmentosum (XP) is correct: Pyrimidine dimers (specifically thymine dimers) are the hallmark DNA lesion caused by Ultraviolet (UV) radiation [1]. In healthy individuals, these dimers are repaired via the Nucleotide Excision Repair (NER) pathway. Xeroderma pigmentosum is an autosomal recessive disorder characterized by a genetic deficiency in the enzymes required for NER (most commonly UV-specific endonucleases) [1]. Consequently, pyrimidine dimers accumulate, leading to mutations in proto-oncogenes and tumor suppressor genes, which manifests as extreme photosensitivity and a 2000-fold increased risk of skin cancers (BCC, SCC, and Melanoma) [1]. 2. Why other options are incorrect: * Alkylating agents (Option B): These are chemical mutagens that typically cause the cross-linking of DNA strands or the addition of methyl/ethyl groups to bases (e.g., O6-methylguanine), rather than pyrimidine dimers. * X-rays and Gamma rays (Options C & D): These represent ionizing radiation [1]. Unlike UV light, ionizing radiation causes cell injury by generating free radicals (indirect action) or by causing single and double-strand DNA breaks and particulate damage [1]. They do not specifically produce pyrimidine dimers. High-Yield Clinical Pearls for NEET-PG: * NER Pathway: Remember the mnemonic "NER is for UV"—Nucleotide Excision Repair fixes UV damage [1]. * Clinical Triad of XP: Severe sunburn on minimal exposure, "parchment-like" skin (xeroderma), and hyperpigmented macules (freckling). * Associated Cancers: XP patients often develop skin malignancies before the age of 10 [1]. * Other Repair Defects: Contrast XP with Lynch Syndrome (Mismatch Repair defect) and Ataxia-Telangiectasia (defect in repair of double-strand breaks caused by ionizing radiation) [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 322-323.

Question 1

Which of the following is associated with chronic granulomatous disease?

Accepted Answer

Associated with formation of multiple granulomas

Answer

A benign neoplastic process

Answer

A parasitic disease

Answer

Acquired leukocyte function defect

Question 2

Which cation is found in extremely high concentrations in cells that have undergone coagulative necrosis?

Accepted Answer

Calcium

Answer

Potassium

Answer

Iron

Answer

Cobalt

Question 3

Which of the following is a growth factor oncogene?

Accepted Answer

sis

Answer

myc

Answer

fos

Answer

jun

Question 4

Which syndrome is characterized by Trisomy 13?

Accepted Answer

Patau Syndrome

Answer

Edward Syndrome

Answer

Down Syndrome

Answer

Turner Syndrome

Question 5

Amyloid-like stroma is seen in which of the following tumors?

Accepted Answer

Medullary tumor

Answer

Papillary tumor

Answer

Follicular tumor

Answer

Anaplastic tumor

Question 6

The activation of caspases is likely to lead to what?

Accepted Answer

Apoptotic cell death

Answer

Blood coagulation

Answer

Mitotic cell division

Answer

G1 to S phase of cell cycle

Question 7

Pyrimidine dimers are a characteristic feature in which condition?

Accepted Answer

Xeroderma pigmentosum

Answer

Alkylating agents

Answer

X-rays

Answer

Gamma rays

Question 8

Myoglobinuria is associated with which of the following?

Accepted Answer

Crush injury

Answer

Tumours

Answer

Electrical injury

Answer

All of the above

Question 9

Which type of cells are most dependent on IFN-γ?

Accepted Answer

IFN-γ

Answer

IL-4

Answer

IL-5

Answer

IL-6

Question 10

What is the characteristic histological finding of Leser-Trélat sign?

Accepted Answer

Seborrheic keratosis

Answer

Actinic keratosis

Answer

Basal cell carcinoma

Answer

Squamous cell carcinoma

General Pathology — MCQs

General Pathology — MCQs

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