Neoplasia Practice Questions

Q: Which of the following does not describe a documented mechanism of tumor-mediated immune evasion?

Antigenic variation. **Explanation:** The correct answer is **Antigenic variation**. While common in pathogens (like *Trypanosoma* or Influenza), antigenic variation is not a primary mechanism for tumor evasion. Tumors typically evade the immune system by suppressing the response or hiding their identity, rather than rapidly changing their surface proteins to stay ahead of antibodies. **Why the other options are documented mechanisms:** * **Downregulation of Class I MHC:** Tumors often stop expressing MHC-I molecules. Since CD8+ T-cells require MHC-I to recognize "non-self" tumor antigens, this makes the tumor "invisible" to cytotoxic T-lymphocytes. * **Secretion of TGF-β:** Tumors create an immunosuppressive microenvironment by secreting cytokines like **TGF-β** and **IL-10**. These inhibit T-cell activation and promote the recruitment of Regulatory T-cells (Tregs), which dampen the immune response. * **Secretion of Decoy Molecules:** Some tumors shed their surface antigens as soluble "decoy" molecules. These bind to circulating antibodies or T-cell receptors before they can reach the actual tumor cell, effectively neutralizing the immune attack. **High-Yield Clinical Pearls for NEET-PG:** * **Immune Checkpoints:** Tumors often upregulate **PD-L1**, which binds to PD-1 on T-cells, sending an inhibitory signal that "shuts down" the T-cell (T-cell exhaustion). * **Fas Ligand (FasL):** Some tumors express FasL to induce apoptosis (programmed cell death) in infiltrating T-cells that attempt to attack them. * **NK Cells:** While MHC-I downregulation helps evade T-cells, it theoretically makes tumors vulnerable to **Natural Killer (NK) cells**, which follow the "missing self" hypothesis. However, tumors often evolve additional mechanisms to inhibit NK cell receptors.

Q: Which of the following parotid malignancies is known for perineural spread?

Adenoid cystic carcinoma. **Explanation:** **Adenoid Cystic Carcinoma (ACC)** is the correct answer because it is classically characterized by its high propensity for **perineural invasion (PNI)**. In the context of the parotid gland, the tumor cells tend to track along the facial nerve (CN VII), often leading to facial nerve palsy—a clinical hallmark that distinguishes it from benign lesions. Histologically, it presents with a "Swiss-cheese" (cribriform) pattern, and its ability to spread along nerve sheaths often results in recurrence and late distant metastasis, even years after surgery. **Analysis of Incorrect Options:** * **Pleomorphic Adenoma (A):** This is the most common benign salivary gland tumor. While it can recur if the capsule is breached during surgery, it does not exhibit perineural spread. * **Warthin’s Tumor (C):** Also known as Papillary Cystadenoma Lymphomatosum, this is a benign tumor strongly associated with smoking. It is typically found in the tail of the parotid and does not invade nerves. * **Ductal Papilloma (D):** This is a rare, benign epithelial tumor of the salivary ducts. It lacks the invasive characteristics required for perineural spread. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for ACC:** Submandibular gland (though it occurs in the parotid, it is the most common malignant tumor of the minor salivary glands) [1]. * **Histological Hallmark:** Cribriform pattern with "cylindromatous" appearance (basement membrane-like material in spaces). * **Clinical Sign:** Pain is a frequent early symptom in ACC due to its affinity for nerves. * **Prognosis:** Characterized by a "relentless" course; 5-year survival is good, but 10-20 year survival is poor due to late metastases (often to the lungs). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 753-755.

Question 1

Which of the following does not describe a documented mechanism of tumor-mediated immune evasion?

Accepted Answer

Antigenic variation

Answer

Down regulation of class I MHC

Answer

Secretion of TGF-b

Answer

Secretion of decoy molecules

Question 2

Which of the following parotid malignancies is known for perineural spread?

Accepted Answer

Adenoid cystic carcinoma

Answer

Pleomorphic adenoma

Answer

Warthin's tumor

Answer

Ductal papilloma

Question 3

A 54-year-old woman diagnosed with early-stage breast cancer undergoes lumpectomy. The pathology report confirms the early stage and notes significant desmoplasia in the surrounding tissue. What does the term desmoplasia refer to?

Accepted Answer

Proliferation of non-neoplastic fibrous connective tissue.

Answer

An irregular accumulation of blood vessels.

Answer

Scanty connective tissue causing the neoplasm to be soft and fleshy.

Answer

Normal tissue misplaced within another organ.

Question 4

A patient presents with a mediastinal mass showing sheets of epithelial cells with an arborizing pattern and positivity for keratin, interspersed with lymphoid cells. What is the most likely diagnosis?

Accepted Answer

Thymoma

Answer

Thymic carcinoid

Answer

Primary mediastinal lymphoma

Answer

Non-Hodgkin lymphoma

Question 5

Which among the following is a marker of carcinoma?

Accepted Answer

Cytokeratin

Answer

Vimentin

Answer

Calretinin

Answer

CD 45

Question 6

BRCA2 gene is associated with all of the following malignancies except?

Accepted Answer

Uterine cancer

Answer

Breast cancer in men

Answer

Breast cancer in women

Answer

Ovarian cancer

Question 7

BRCA1 gene is located on which chromosome?

Accepted Answer

Chromosome 17

Answer

Chromosome 13

Answer

Chromosome 11

Answer

Chromosome 22

Question 8

A patient with a known mutation in the RB gene is disease-free from Retinoblastoma. The patient is at highest risk of developing which of the following malignancies?

Accepted Answer

Osteosarcoma

Answer

Renal cell carcinoma

Answer

Pinealoblastoma

Answer

Chondrosarcoma

Question 9

An 8-year-old boy presented with a skin tumor on his left cheek. He had always avoided exposure to sunlight because it made his skin blister. His skin had scattered areas of hyperpigmentation. What is the most likely underlying defect?

Accepted Answer

Defective DNA repair

Answer

Thymidine dimers

Answer

Trinucleotide repeats

Answer

Sugar changes

Question 10

Which of the following is NOT associated with tumor suppressor gene dysfunction?

Accepted Answer

Multiple endocrine neoplasia

Answer

Breast cancers

Answer

Neurofibromatosis

Answer

Retinoblastoma

Neoplasia — MCQs

Neoplasia — MCQs

On this page

Practice by Chapter

Want unlimited practice?