Neoplasia Practice Questions

Q: NNK, NNN, and polonium 210 are carcinogens specific for which type of cancer?

Tobacco-related oral cancer. ### Explanation The correct answer is **A. Tobacco-related oral cancer.** **Understanding the Concept:** Tobacco contains over 60 known carcinogens. Among these, **Tobacco-Specific Nitrosamines (TSNAs)** are the most potent. * **NNK** [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] and **NNN** (N-nitrosonornicotine) are formed by the nitrosation of nicotine during the curing and processing of tobacco [2]. * **Polonium-210** is a radioactive alpha-emitter absorbed by tobacco leaves from phosphate fertilizers. While these are found in cigarette smoke, they are uniquely concentrated in **smokeless tobacco (chewing tobacco/snuff)**. NNN and NNK undergo metabolic activation to form DNA adducts, leading to mutations in the oral mucosa, making them the primary drivers for **oral cavity cancers**. **Analysis of Incorrect Options:** * **B. Bronchogenic Carcinoma:** While NNK is a systemic carcinogen that can cause lung cancer, the primary drivers for lung cancer in smokers are **Polycyclic Aromatic Hydrocarbons (PAHs)** like Benzo[a]pyrene [1]. * **C. Prostatic Carcinoma:** This is primarily linked to age, genetics (BRCA2), and hormonal factors (androgens), rather than specific tobacco nitrosamines. * **D. Hepatocellular Carcinoma:** The major risk factors are Chronic Hepatitis B/C, Alcohol, and **Aflatoxin B1** (produced by *Aspergillus*) [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Most potent TSNA:** NNK is considered the most carcinogenic. * **Benzo[a]pyrene:** The classic "high-yield" carcinogen associated with cigarette smoke and lung cancer (induces *TP53* mutations). * **Vinyl Chloride:** Associated with Angiosarcoma of the liver. * **Beta-naphthylamine:** Associated with Transitional Cell Carcinoma (TCC) of the bladder in dye industry workers [1].

Q: A tumor that is negative for CK7 and CK20 is most likely which of the following?

Prostate carcinoma. In immunohistochemistry (IHC), the combination of **Cytokeratin 7 (CK7)** and **Cytokeratin 20 (CK20)** is a fundamental diagnostic algorithm used to determine the primary site of an unknown metastatic tumor. ### **Explanation of the Correct Answer** **A. Prostate Carcinoma:** Most prostate adenocarcinomas are characteristically **CK7 negative and CK20 negative** [1]. This "double negative" profile is a high-yield diagnostic marker. To confirm prostate origin, pathologists typically use more specific markers like **PSA (Prostate Specific Antigen)** or **PSMA** [1]. ### **Analysis of Incorrect Options** * **B. Colon Carcinoma:** Classically follows a **CK7– / CK20+** pattern. This is the "signature" profile for colorectal adenocarcinoma. * **C. Urothelial Carcinoma:** Typically shows a **CK7+ / CK20+** (double positive) pattern. This helps differentiate it from prostate cancer, which often presents with similar clinical symptoms. * **D. Mesothelioma:** Characteristically **CK7+ / CK20–**. It also expresses specific markers like Calretinin and WT-1. ### **High-Yield Clinical Pearls for NEET-PG** * **CK7+/CK20– Profile:** Seen in Lung (adenocarcinoma), Breast, Thyroid, and Endometrial cancers. * **CK7–/CK20+ Profile:** Highly suggestive of Colorectal cancer and Merkel cell carcinoma. * **CK7+/CK20+ Profile:** Seen in Urothelial (Bladder), Pancreatic, and Gastric cancers. * **CK7–/CK20– Profile:** Seen in **Prostate cancer**, Renal Cell Carcinoma (RCC), and Hepatocellular Carcinoma (HCC) [1]. * **Memory Aid:** "Prostate and Kidney (RCC) are 'double negative' (7-/20-), while the Bladder (Urothelial) is 'double positive' (7+/20+)." **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lower Urinary Tract and Male Genital System, pp. 989-994.

Question 1

The tumor suppressor gene P53 induces cell arrest at which phase?

Accepted Answer

G1-S phase

Answer

G2-M phase

Answer

S-G2 phase

Answer

G0 phase

Question 2

NNK, NNN, and polonium 210 are carcinogens specific for which type of cancer?

Accepted Answer

Tobacco-related oral cancer

Answer

Tobacco-related bronchogenic carcinoma

Answer

Prostatic carcinoma

Answer

Hepatocellular carcinoma

Question 3

Kaposi sarcoma is commonly seen in which condition?

Accepted Answer

AIDS

Answer

Leukemia

Answer

Lymphoma

Answer

Cytomegalovirus infections

Question 4

All of the following are precancerous conditions except?

Accepted Answer

SLE

Answer

Peutz-Jeghers syndrome

Answer

Plummer-Vinson syndrome

Answer

Xeroderma pigmentosum

Question 5

All of the following changes are seen in dysplasia of the squamo-columnar junction, except?

Accepted Answer

Breaking of the basement membrane

Answer

Change of epithelium

Answer

Hyperchromatic nuclei

Answer

Increased mitotic figures

Question 6

Arrange the following steps in oncogenesis in the correct sequence:

Accepted Answer

Activation of proto-oncogene, Warburg effect, increased activity of telomerase, angiogenesis, Evasion of host defense

Answer

increased activity of telomerase, angiogenesis, Evasion of host defense, Activation of proto-oncogene, Warburg effect

Answer

increased activity of telomerase, angiogenesis, Evasion of host defense, Activation of proto-oncogene, Warburg effect

Answer

Activation of proto-oncogene, Warburg effect, Evasion of host defense, angiogenesis, increased activity of telomerase

Question 7

Which of the following statements regarding the PTEN gene is NOT true?

Accepted Answer

It acts as a proto-oncogene.

Answer

It is a membrane-associated phosphatase.

Answer

It is encoded by a gene located on chromosome 10q23.

Answer

It is frequently mutated in endometrial, breast, and thyroid carcinomas.

Question 8

A 55-year-old man presents with a solitary breast mass, and biopsy reveals malignant cells. Immunohistochemical staining shows that the tumor cells are positive for estrogen receptor (ER) and negative for Her2/neu. What is the most likely diagnosis?

Accepted Answer

Invasive ductal carcinoma

Answer

Basal cell carcinoma

Answer

Medullary carcinoma

Answer

Tubular adenoma

Question 9

Which of the following is not considered a pre-malignant condition at some site?

Accepted Answer

Bronchiectasis

Answer

Cholelithiasis

Answer

Ulcerative colitis

Answer

Leukoplakia

Question 10

A tumor that is negative for CK7 and CK20 is most likely which of the following?

Accepted Answer

Prostate carcinoma

Answer

Colon carcinoma

Answer

Urothelial carcinoma

Answer

Mesothelioma

Neoplasia — MCQs

Neoplasia — MCQs

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