Neoplasia Practice Questions

Q: Which enzymatic activity is primarily responsible for the immortality of cancer cells?

Telomerase. ***Telomerase*** - **Telomerase** is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes (**telomeres**), preventing their shortening during DNA replication [1]. - In normal somatic cells, **telomerase** activity is low or absent, leading to progressive telomere shortening and eventual cellular senescence or apoptosis; however, in cancer cells, **telomerase** is highly active, maintaining telomere length and enabling indefinite cell division, contributing to their **immortality** [1]. *DNA reverse transcriptase* - **DNA reverse transcriptase** synthesizes DNA from an RNA template, a process characteristic of retroviruses (e.g., HIV) and not typically involved in the immortality of human cancer cells. - While some endogenous retroelements exist in the human genome, this enzyme's primary role is not in maintaining the replicative potential of cancer cells. *RNA polymerase* - **RNA polymerase** is responsible for synthesizing RNA from a DNA template (**transcription**), a fundamental process in gene expression. - While critical for cell growth and division, **RNA polymerase** does not directly prevent telomere shortening or contribute to cellular immortality. *DNA polymerase* - **DNA polymerase** is involved in DNA replication and repair, synthesizing new DNA strands and ensuring genetic fidelity. - While essential for cell proliferation, it does not directly address the issue of **telomere shortening**, which is key to cellular aging and immortality. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 311-312.

Q: CA-19-9 is typically elevated in all of the following cancers except:

Breast carcinoma. ***Breast carcinoma*** - CA-19-9 is a **tumor marker** primarily associated with **gastrointestinal cancers** and is not typically elevated in breast carcinoma. - While other markers like **CA 15-3** or **CA 27.29** are used for monitoring breast cancer, CA-19-9 is not clinically useful in this context. *Ovarian carcinoma* - Although **CA-125** is the primary marker for ovarian cancer, CA-19-9 can be elevated in a subset of cases, particularly with **mucinous ovarian tumors**. - Its presence can indicate a **different histological subtype** or more advanced disease, but it's not the primary diagnostic marker. *Colonic carcinoma* - CA-19-9 can be elevated in **colorectal cancer**, although **CEA (carcinoembryonic antigen)** is more commonly used for monitoring this type of cancer. - High levels of CA-19-9 in colorectal cancer may suggest **advanced disease** or specific tumor characteristics. *Pancreatic carcinoma* - CA-19-9 is the **most widely used and validated tumor marker** for **pancreatic adenocarcinoma**, helping in diagnosis, prognosis, and monitoring treatment response. - Elevated levels are found in a majority of patients with pancreatic cancer and correlate with **tumor burden** and **disease progression**.

Q: Which of the following tumors is known for its potential for spontaneous regression?

Malignant melanoma. ***Osteogenic sarcoma*** - Osteogenic sarcoma, or **osteosarcoma**, is a **malignant bone tumor** that typically does not resolve spontaneously and often requires aggressive treatment [1]. - It commonly presents with **pain and swelling** in long bones, and its prognosis is poor without intervention. *Retinoblastoma* - Retinoblastoma can exhibit **spontaneous regression**, especially in bilateral cases, where the tumor may shrink without treatment over time. - It primarily affects the **retina** in children, ideally diagnosed early to preserve vision and life. *Cholangio carcinoma* - Cholangio carcinoma is an aggressive form of **bile duct cancer** that does not resolve spontaneously and usually has a poor prognosis. - Symptoms typically include **jaundice** and bile duct obstruction, requiring surgical intervention. *Malignant melanoma* - Malignant melanoma is a highly aggressive skin cancer that does not undergo spontaneous resolution and often metastasizes quickly. - Early recognition is crucial for treatment, as it is associated with significant **morbidity and mortality**. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.

Q: Clear cell variety of renal cell carcinoma is related to a gene located on which chromosome?

3. ***3*** - The **clear cell variety of renal cell carcinoma** (RCC) is associated with **mutations in the VHL gene**, which is located on chromosome **3** [1]. - This gene plays a crucial role in the **regulation of angiogenesis**, and its inactivation leads to tumor development. *22* - Chromosome **22** is associated with other disorders but not specifically with clear cell RCC or its genetic mutations. - Renal cell carcinoma primarily relates to **chromosome 3**, not chromosome 22 [1]. *X* - The **X chromosome** has other oncogenes and tumor suppressor genes but is not linked to clear cell RCC specifically. - Mutations in the **VHL gene** on chromosome 3 are the key factors, not those found on the X chromosome. *20* - Chromosome **20** does not contain significant genes linked to clear cell renal cell carcinoma. - The notable genetic association is with chromosome **3**, specifically the VHL gene [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 958-959.

Q: All are features of hypernephroma except:

Lower pole involvement. ***Lower pole involvement*** - Renal cell carcinoma (hypernephroma) characteristically shows a **predilection for the upper pole** of the kidney, occurring in approximately **70-75% of cases** [1]. - **Lower pole involvement is NOT a typical feature** and occurs less frequently. - This upper pole predilection is an important distinguishing characteristic of RCC. *Cannon ball secondaries are seen* - **Cannonball metastases** (large, round, well-circumscribed lesions) are a characteristic radiographic finding when renal cell carcinoma metastasizes to the **lungs**. - This appearance is highly suggestive of advanced renal cell carcinoma. *More common in males* - Renal cell carcinoma consistently shows a higher incidence in **males than females**, with a male-to-female ratio of approximately **2:1** [1]. - This **gender predisposition** is well-established in epidemiological studies. *May invade renal vein* - **Renal vein invasion** is a classic and critical feature of renal cell carcinoma, which can extend into the **inferior vena cava** [1]. - This venous invasion is a significant factor in **staging and prognosis** [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 959-961.

Question 1

Which enzymatic activity is primarily responsible for the immortality of cancer cells?

Accepted Answer

Telomerase

Answer

RNA polymerase

Answer

DNA polymerase

Answer

DNA reverse transcriptase

Question 2

CA-19-9 is typically elevated in all of the following cancers except:

Accepted Answer

Breast carcinoma

Answer

Ovarian carcinoma

Answer

Colonic carcinoma

Answer

Pancreatic carcinoma

Question 3

Which of the following tumors is known for its potential for spontaneous regression?

Accepted Answer

Malignant melanoma

Answer

Osteogenic sarcoma

Answer

Retinoblastoma

Answer

Cholangiocarcinoma

Question 4

Clear cell variety of renal cell carcinoma is related to a gene located on which chromosome?

Accepted Answer

3

Answer

X

Answer

22

Answer

20

Question 5

All are features of hypernephroma except:

Accepted Answer

Lower pole involvement

Answer

Cannon ball secondaries are seen

Answer

More common in males

Answer

May invade renal vein

Neoplasia — MCQs

Neoplasia — MCQs

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