Neoplasia Practice Questions

Q: What is the most specific immunohistochemical marker for melanoma cells?

HMB-45. ### Explanation **Correct Answer: C. HMB-45** **Why HMB-45 is the correct answer:** HMB-45 (Human Melanoma Black-45) is a monoclonal antibody that reacts against **gp100**, a glycoprotein found in premelanosomes. It is considered the **most specific** marker for melanoma because it is absent in most non-melanocytic tumors and normal adult melanocytes (except fetal/activated ones) [1]. While its sensitivity is lower than S-100, its high specificity makes it the gold standard for confirming a melanocytic origin in a poorly differentiated tumor. **Analysis of Incorrect Options:** * **A. S-100:** This is the **most sensitive** marker for melanoma. However, it is **not specific** as it is also expressed in cells of neural crest origin, including Schwann cells, glial cells, chondrocytes, and Langerhans cells. * **B. Melan-A (MART-1):** This is a very useful marker for melanocytic differentiation. While highly sensitive and more specific than S-100, HMB-45 remains the classic textbook answer for "most specific" due to its lack of staining in resting normal melanocytes. * **D. Chromogranin:** This is a marker for **neuroendocrine tumors** (e.g., carcinoid, small cell carcinoma) and has no role in the diagnosis of melanoma. **High-Yield Clinical Pearls for NEET-PG:** * **Most Sensitive Marker:** S-100 (Best for screening/ruling out). * **Most Specific Marker:** HMB-45 (Best for ruling in) [1]. * **Newer Highly Specific Marker:** **SOX10** is gaining prominence in recent literature as both highly sensitive and specific for melanoma and spindle cell variants. * **Vimentin:** Melanomas are almost always Vimentin positive (mesenchymal origin marker). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1151-1152.

Question 1

Where are the BRCA-1 and BRCA-2 genes located, respectively?

Accepted Answer

Chromosome 17 and Chromosome 13

Answer

Chromosome 17 and Chromosome 22

Answer

Chromosome 22 and Chromosome 17

Answer

Chromosome 13 and Chromosome 17

Question 2

Which of the following is associated with a moderately increased risk for invasive breast carcinoma?

Accepted Answer

Atypical ductal hyperplasia

Answer

Sclerosing adenoma

Answer

Apocrine metaplasia

Answer

Duct ectasia

Question 3

A study of women with breast carcinoma is done to determine the presence and amount of estrogen receptor (ER) and progesterone receptor (PR) in the carcinoma cells. Large amounts of ER and PR are found in the carcinoma cells of some patients, while these receptors are not present in the cells of other patients. Patients with positivity for ER and PR are likely to exhibit which of the following traits?

Accepted Answer

Higher response to therapy

Answer

Greater immunogenicity

Answer

Greater likelihood of metastases

Answer

Greater risk of familial breast cancer

Question 4

"Basal-like" carcinoma of breast can be identified as:

Accepted Answer

Estrogen Receptor (ER) -ve; HER2 -ve

Answer

Estrogen Receptor (ER) +ve; HER2 -ve

Answer

HER2 +ve

Answer

Estrogen Receptor (ER) +ve; HER2 +ve

Question 5

Thymoma can be associated with all of the following conditions, EXCEPT:

Accepted Answer

Hypergammaglobulinemia

Answer

Superior mediastinum syndrome

Answer

Myasthenia gravis

Answer

Pure red cell aplasia

Question 6

Which of the following is NOT a malignant feature?

Accepted Answer

Aplasia

Answer

Anaplasia

Answer

Abnormal mitosis

Answer

Pleomorphism

Question 7

Which of the following statements about chromothrypsis is NOT true?

Accepted Answer

It is associated with inactivation of tumor suppressor genes and activation of oncogenes.

Answer

It is associated with chromosome rearrangements termed as chromosome shattering.

Answer

It is observed in 1% to 2% of cancers as a whole.

Answer

It has an increased frequency in 25% of osteosarcomas and a high frequency in gliomas.

Question 8

A woman who is heterozygous for glucose-6-phosphate dehydrogenase (G6PD), a polymorphic enzyme transcribed from the X chromosome, develops chronic myeloid leukemia. Restriction fragment length polymorphism (RFLP) studies on the tumor cells for G6PD reveal that only a single form of the enzyme is transcribed. This finding supports which of the following features of neoplasia?

Accepted Answer

Monoclonality

Answer

Genetic mutation

Answer

Mosaicism

Answer

Oncogene activation

Question 9

What is the commonest site for the spread of cancers?

Accepted Answer

Lymph Nodes

Answer

Liver

Answer

Lungs

Answer

Brain

Question 10

What is the most specific immunohistochemical marker for melanoma cells?

Accepted Answer

HMB-45

Answer

S-100

Answer

Melan-A

Answer

Chromogranin

Neoplasia — MCQs

Neoplasia — MCQs

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