Tumor Markers — MCQs
Which of the following is a testicular tumor marker?
Which marker is used to differentiate a thymoma from acute lymphoblastic leukemia (ALL)?
Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?
Okuda staging contains all except
CA 19-9 is a marker for which of the following:
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
Diagnosis of carcinoid tumour is done by urinary estimation of:
Which of the following is true about alpha-1 antitrypsin?
Which of the following enzymes is not classified as an oxidoreductase?
Which of the following conditions masks low serum haptoglobin in hemolysis?
Tumor Markers Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is a testicular tumor marker?
- A. HCG (Correct Answer)
- B. CA-125
- C. a-1 antitrypsin
- D. PSA (Prostate Specific Antigen)
Explanation: ***HCG*** - **Human Chorionic Gonadotropin (HCG)** is a key tumor marker for **germ cell tumors** of the testis, especially **choriocarcinoma** and some **seminomas** [1]. - Its levels correlate with tumor burden and are used for diagnosis, staging, and monitoring response to treatment. *CA-125* - **CA-125** is primarily used as a tumor marker for **ovarian cancer**, not testicular tumors. - Elevated levels can also be seen in other conditions affecting the peritoneum or pleura. *a-1 antitrypsin* - **Alpha-1 antitrypsin** is a protein involved in inhibiting proteases, and its deficiency is linked to **emphysema** and **liver disease**, not testicular cancer. - It is not considered a tumor marker for any specific cancer. *PSA (Prostate Specific Antigen)* - **PSA** is a well-known tumor marker for **prostate cancer**, primarily used for screening, diagnosis, and monitoring treatment efficacy in men [1], [2]. - It is produced by the prostate gland and is not associated with testicular tumors.
Question 2: Which marker is used to differentiate a thymoma from acute lymphoblastic leukemia (ALL)?
- A. Cytokeratin (Correct Answer)
- B. CD1a
- C. CD3
- D. TdT
Explanation: ***Cytokeratin*** - **Thymomas** are epithelial tumors and express **cytokeratin**, which is a marker for epithelial cells, while **ALL** (Acute Lymphoblastic Leukemia) does not express this marker. - The presence of **cytokeratin** indicates a **thymic origin**, differentiating it from lymphoid neoplasms like **ALL**. *CD1a* - This marker is primarily associated with **Hodgkin's lymphoma** and some **T-cell neoplasms**, not thymomas [2]. - The lack of expression in **ALL** makes it an unsuitable differentiator for thymomas. *Tdt* - **Tdt** (Terminal deoxynucleotidyl transferase) is a marker typically found in lymphoid progenitor cells, especially in **ALL**. - Its presence would not indicate a **thymoma**, which does not express **Tdt**. *CD3* - While **CD3** is a marker of **T-cells** [2], it is not specific for thymomas, which can be **CD3-positive**, but it is also seen in various **lymphoid proliferations** including **ALL** [1]. - Therefore, it cannot be definitively used to distinguish between a thymoma and **ALL**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 599-600. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 598.
Question 3: Which of the following is the platinum-based chemotherapeutic agent used as first-line treatment for ovarian carcinoma?
- A. Cyclophosphamide
- B. Methotrexate
- C. Cisplatin (Correct Answer)
- D. Dacarbazine
Explanation: ***Cisplatin*** - **Cisplatin** is a platinum-based chemotherapy drug that forms **DNA cross-links**, inhibiting DNA synthesis and leading to the death of rapidly dividing cells, making it highly effective against **ovarian carcinoma**. - It is a cornerstone of chemotherapy regimens for ovarian cancer, often used in combination with other agents such as paclitaxel. *Methotrexate* - **Methotrexate** is an **antimetabolite** that inhibits dihydrofolate reductase, thereby interfering with DNA synthesis. - While it is used in various cancers like leukemia, lymphoma, and some solid tumors (e.g., breast cancer, gestational trophoblastic disease), it is **not a primary recommended drug for ovarian carcinoma**. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that causes DNA damage, leading to cell death. - It is used in many cancers, including lymphoma, breast cancer, and some leukemias, but it is **not a first-line or primary agent for ovarian carcinoma** in contemporary treatment guidelines. *Dacarbazine* - **Dacarbazine** is an **alkylating agent** primarily used in the treatment of **malignant melanoma** and Hodgkin lymphoma. - It is **not indicated for the treatment of ovarian carcinoma**.
Question 4: Okuda staging contains all except
- A. AFP (Correct Answer)
- B. Tumor size
- C. Ascites
- D. Bilirubin
Explanation: ***AFP*** - The **Okuda staging system** for hepatocellular carcinoma (HCC) uses parameters related to liver function and tumor burden, but it does **not include AFP levels**. [1] - AFP is a common **tumor marker** for HCC but is not part of the specific criteria for Okuda staging. *Tumor size* - **Tumor size greater than 50%** of the liver parenchyma is one of the four parameters used in the Okuda staging system. - This criterion is crucial for assessing the **extent of the disease**, differentiating between early and advanced cases. *Ascites* - The presence of **ascites** (related to fluid retention) is another key parameter in the Okuda staging system. - Ascites indicates **decompensated liver function**, implying a more advanced stage of disease. *Bilirubin* - **Bilirubin levels higher than 3 mg/dL** are included in the Okuda staging system. - Elevated bilirubin reflects **severe liver dysfunction**, indicating reduced hepatic synthetic capacity and usually a poorer prognosis.
Question 5: CA 19-9 is a marker for which of the following:
- A. Breast carcinoma
- B. Lung carcinoma
- C. Ovarian carcinoma
- D. Pancreatic carcinoma (Correct Answer)
Explanation: ***Pancreatic carcinoma*** - **CA 19-9** is a widely used **tumor marker** primarily associated with **pancreatic cancer** [1]. - Its levels can be elevated in other conditions such as **cholangitis** or **gallstones**, but its most significant clinical utility is in monitoring pancreatic cancer progression and response to treatment [2], [4]. *Breast carcinoma* - The primary tumor markers for breast carcinoma are **CA 15-3** and **CA 27-29**, which are used for monitoring recurrence and treatment response. - While CA 19-9 can be slightly elevated in some breast cancer cases, it is not considered a primary or reliable marker for this type of cancer. *Lung carcinoma* - Common tumor markers for lung cancer include **CEA** (carcinoembryonic antigen) for non-small cell lung cancer and **NSE** (neuron-specific enolase) for small cell lung cancer [3]. - CA 19-9 has very limited utility in the diagnosis or monitoring of lung carcinoma. *Ovarian carcinoma* - **CA-125** is the primary tumor marker used for ovarian carcinoma, particularly for monitoring disease progression and treatment response. - Although CA 19-9 can be elevated in some gynecological malignancies, it is not the marker of choice for ovarian cancer.
Question 6: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 7: Diagnosis of carcinoid tumour is done by urinary estimation of:
- A. VMA
- B. Metanephrines
- C. Catecholamines
- D. 5HIAA (Correct Answer)
Explanation: ***5HIAA*** - The urinary estimate of **5-hydroxyindoleacetic acid (5HIAA)** is the primary diagnostic test for **carcinoid tumors** [1], particularly those secreting serotonin. - Elevated levels of **5HIAA** in urine indicate excessive serotonin production, which is characteristic of these tumors. *VMA* - **Vanillylmandelic acid (VMA)** is a metabolite of catecholamines and is primarily used in diagnosing **neuroblastoma** or **pheochromocytoma**, not carcinoid tumors. - Although it indicates catecholamine secretion, it does not correlate with **serotonin** levels associated with carcinoid tumors. *Metanephrines* - **Metanephrines** represent metabolites of catecholamines and are mainly evaluated for **pheochromocytoma**. - They do not provide information on serotonin metabolism or carcinoid tumor activity. *Catecholamines* - Catecholamines such as **epinephrine and norepinephrine** are not specifically related to carcinoid tumors and often indicate other neuroendocrine tumors. - Their levels do not correlate with serotonin or its metabolite, **5HIAA**, used for carcinoid diagnosis. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 12-15.
Question 8: Which of the following is true about alpha-1 antitrypsin?
- A. Inhibits elastase (Correct Answer)
- B. Inhibits trypsin
- C. Inhibits chymotrypsin
- D. Inhibits trypsinogen activation
Explanation: ***Inhibits elastase*** - Alpha-1 antitrypsin (A1AT) primarily serves to **inhibit elastase**, a protease that can damage lung tissue, helping to protect the lungs from destruction [1]. - Deficiency of A1AT leads to **emphysema** and liver disease due to unchecked activity of elastase [1][2]. *Inhibits trypsin* - A1AT specifically does not primarily inhibit **trypsin**, which is involved in protein digestion in the intestine. - Although A1AT affects proteases, its main function is related to **elastase**, not trypsin [1]. *Inhibits trypsinogen activation in pancreas* - A1AT does not have a significant role in the **inhibition of trypsinogen activation** within the pancreas. - Instead, pancreatic enzyme regulation involves other mechanisms that do not involve A1AT's function. *Inhibits chymotrypsin* - A1AT is not known for inhibiting **chymotrypsin**, a serine protease derived from trypsinogen in the gut. - It specifically targets **elastase** and similar enzymes rather than chymotrypsin [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, pp. 856-858. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 683-684.
Question 9: Which of the following enzymes is not classified as an oxidoreductase?
- A. Alcohol dehydrogenase
- B. Catalase
- C. Peroxidase
- D. Glucokinase (Correct Answer)
Explanation: ***Glucokinase*** - **Glucokinase** is a **transferase** enzyme that catalyzes the transfer of a phosphate group from ATP to glucose, forming glucose-6-phosphate. - Its function is primarily in **glucose metabolism** and **insulin secretion**, not in oxidation or reduction reactions. *Catalase* - **Catalase** is an **oxidoreductase** that catalyzes the decomposition of **hydrogen peroxide** into water and oxygen. - This reaction involves the **oxidation and reduction** of substrates, fitting the definition of an oxidoreductase. *Alcohol dehydrogenase* - **Alcohol dehydrogenase** is an **oxidoreductase** that catalyzes the interconversion between alcohols and aldehydes or ketones with the concomitant reduction and oxidation of **NAD+** to **NADH**. - This enzyme is crucial in **detoxifying alcohol** by oxidizing it and is a classic example of an oxidoreductase. *Peroxidase* - **Peroxidase** is an **oxidoreductase** that catalyzes the oxidation of a substrate by **hydrogen peroxide**. - Peroxidases work by using hydrogen peroxide to accept electrons from another molecule, thereby **oxidizing** that molecule.
Question 10: Which of the following conditions masks low serum haptoglobin in hemolysis?
- A. Bile duct obstruction (Correct Answer)
- B. Liver disease
- C. Malnutrition
- D. Pregnancy
Explanation: **Explanation:** The primary clinical utility of **Haptoglobin** is as a marker for **intravascular hemolysis**. Haptoglobin is an acute-phase reactant synthesized by the liver that binds free hemoglobin. During hemolysis, haptoglobin levels drop significantly as it is cleared by the reticuloendothelial system. **Why Bile Duct Obstruction is correct:** Haptoglobin is a **positive acute-phase reactant**. In conditions like **bile duct obstruction (obstructive jaundice)**, inflammation or biliary stasis triggers an increase in the hepatic synthesis of haptoglobin. This elevation can artificially "mask" or normalize the low levels typically seen in hemolysis, leading to a false-negative result for hemolytic anemia. **Analysis of Incorrect Options:** * **Liver Disease:** Since haptoglobin is synthesized in the liver, severe liver disease (e.g., cirrhosis) leads to **decreased** production. This would mimic or exacerbate low levels rather than masking them. * **Malnutrition:** Protein-energy malnutrition leads to a generalized decrease in plasma protein synthesis, including haptoglobin, resulting in **low** levels. * **Pregnancy:** Pregnancy is associated with a physiological decrease in haptoglobin levels (estrogen effect), which would not mask a hemolytic state. **NEET-PG High-Yield Pearls:** * **Gold Standard for Hemolysis:** A **decreased** serum haptoglobin level is one of the most sensitive markers for confirming hemolysis. * **Acute Phase Reactants:** Remember that haptoglobin levels rise in infection, trauma, and malignancy, which can confound the diagnosis of co-existing hemolysis. * **Neonate Fact:** Haptoglobin levels are naturally very low or absent in newborns (physiologic ahaptoglobinemia) and reach adult levels by 6 months of age.
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