Cancer Biology Basics — MCQs
Cancer cells preferentially utilize glycolysis for energy production even in the presence of adequate oxygen. What is this phenomenon called?
Which of the following substances is a growth factor that is capable of inducing all the steps necessary for angiogenesis?
In the context of bone metastasis, which of the following bones is least likely to be a site of metastasis?
Which phase of the cell cycle does not have a fixed duration?
Most radio-resistant phase in the cell cycle:
In which type of lung carcinoma is the p53 mutation most commonly observed?
Which of the following is not an apoptotic gene?
Intraoperative radiation therapy (IORT) is most commonly used in which of the following cancers?
What is the definition of a sentinel lymph node?
What is the definition of neoadjuvant chemotherapy?
Cancer Biology Basics Indian Medical PG Practice Questions and MCQs
Question 1: Cancer cells preferentially utilize glycolysis for energy production even in the presence of adequate oxygen. What is this phenomenon called?
- A. Warburg effect (Correct Answer)
- B. Hypoxic adaptation
- C. Anoxic survival
- D. Oxygen-independent metabolism
Explanation: ***Warburg*** - The **Warburg effect** describes how cancer cells preferentially use glycolysis for energy production even in the presence of oxygen, allowing them to thrive in **hypoxic conditions** [1]. - This metabolic adaptation supports **cell proliferation** and survival in tumor microenvironments where oxygen is limited [1][3]. - Cancer cells upregulate glucose uptake and express specific metabolic enzymes like the M2 isoform of pyruvate kinase that facilitate this altered metabolism [2][4]. *Wanton* - This term typically refers to recklessness or extravagance and is not used in the context of cancer metabolism or hypoxia. - There are no associations with **cancer cell adaptation** under adverse environmental conditions. *Wormian* - **Wormian bones** are extra bone pieces within sutures of the skull, unrelated to cancer cell metabolism or survival mechanisms. - This term does not connect to **hypoxia** or metabolic adaptations in cancer biology. *Wolf* - "Wolf" has no recognized connection to cancer cell biology, particularly regarding metabolic adaptations under **hypoxic stress**. - It does not imply any concept associated with how cancer cells cope with adverse conditions. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 307-308. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 308-310. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 290-291. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 26-27.
Question 2: Which of the following substances is a growth factor that is capable of inducing all the steps necessary for angiogenesis?
- A. TGF -a
- B. PDGF
- C. EGF
- D. Basic fibroblast growth factor (Correct Answer)
Explanation: ***Basic fibroblast growth factor*** - **Basic fibroblast growth factor (bFGF or FGF2)** is a potent inducer of **angiogenesis**, promoting endothelial cell proliferation, migration, and tube formation. - It plays a crucial role in **wound healing** and **tumor growth** by stimulating the development of new blood vessels. *TGF-α* - **TGF-alpha** primarily acts as a **mitogen** for epithelial cells and fibroblasts, promoting cell growth and differentiation. - While it can indirectly influence angiogenesis, it does not directly induce all steps of the process like bFGF. *PDGF* - **Platelet-derived growth factor (PDGF)** is a mitogen for **fibroblasts, smooth muscle cells, and glial cells**, involved in wound healing and tissue remodeling. - Its primary role in angiogenesis is thought to be in the **stabilization of new vessels** by recruiting pericytes and smooth muscle cells, rather than initiating new vessel formation. *EGF* - **Epidermal growth factor (EGF)** primarily stimulates the **proliferation and differentiation of epidermal and epithelial cells**. - While it contributes to tissue repair and cell growth, its direct role in inducing all stages of angiogenesis is less prominent compared to bFGF.
Question 3: In the context of bone metastasis, which of the following bones is least likely to be a site of metastasis?
- A. Femur
- B. Humerus
- C. Fibula (Correct Answer)
- D. Spine
Explanation: ***Fibula*** - The **fibula** is not commonly involved in **metastatic disease**, primarily due to its low blood supply compared to other bones. - While it can occasionally show metastatic lesions, it's **rare** when compared to more commonly affected sites. *Humerus* - The **humerus** can be affected by metastasis, often from lung or breast cancers [1], as it is one of the long bones involved in **hematogenous spread**. - Common presentations include **lytic or blastic lesions**, which indicate bone damage from metastatic processes. *Femur* - The **femur** is frequently involved in metastatic lesions, particularly in patients with malignancies like **prostate or breast cancer** [1]. - Symptoms may include **pain** and **pathologic fractures** due to the weakening of the bone structure from metastasis [1]. *Spine* - The **spine** is a common site for metastases, especially from cancers such as **lung, breast, and prostate** [1]. - Bone scans often reveal **vertebral body lesions**, leading to complications like **spinal cord compression** [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 674-675.
Question 4: Which phase of the cell cycle does not have a fixed duration?
- A. S phase (DNA synthesis)
- B. M phase (mitosis)
- C. G1 phase (cell growth) (Correct Answer)
- D. G2 phase (preparation for mitosis)
Explanation: ***G1*** - The **G1 phase** of the cell cycle is variable in length and can differ significantly between cell types and conditions, unlike S, M, and G2 phases [1][2]. - Cells can spend an **indeterminate amount of time** in G1, depending on factors like nutrients and signals for division [2]. *S* - The **S phase** is characterized by a fixed duration where **DNA replication** occurs, and is critical for cell division [1]. - It typically has a well-defined time frame in the cell cycle that is consistent across different cells [1]. *M* - The **M phase** (mitosis) requires a set duration to ensure that the **cell divides** accurately and equally into two daughter cells [2]. - Fluctuations in this phase can result in aberrant cell division and aneuploidy. *G2* - The **G2 phase** also has a consistent timeframe dedicated to preparing the cell for mitosis, focusing on DNA repair and organelle duplication [2]. - The cell ensures readiness for division during this phase, which is critical for genomic integrity. **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. 78-79. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 37-38.
Question 5: Most radio-resistant phase in the cell cycle:
- A. G2
- B. Late S (Correct Answer)
- C. Early S
- D. G1
Explanation: ***Late S*** - The **late S phase** is the **most radio-resistant phase** of the cell cycle due to high levels of DNA repair enzymes and mechanisms active during this period. - During late S phase, chromatin is **tightly packed** and DNA synthesis is accompanied by robust **homologous recombination repair** capacity, making cells less vulnerable to radiation-induced damage. - This is a well-established principle in radiobiology, with cells in late S showing **2-3 times more resistance** compared to G2/M phases. *Early S* - While S phase overall is relatively radio-resistant, **early S is less resistant than late S** because repair mechanisms are not yet fully upregulated. - DNA replication has just begun, and the cell has moderate levels of repair enzymes compared to late S phase. *G1* - Cells in G1 phase have **moderate radio-sensitivity**, more sensitive than S phase but less sensitive than G2/M phases. - While cells have time for repair in G1, they lack the enhanced repair enzyme levels present during S phase. - G1 cells are in an **active metabolic state** preparing for DNA synthesis. *G2* - G2 phase is one of the **most radio-sensitive phases** along with mitosis (M phase). - Cells have **duplicated DNA** (4n content) and are preparing for division, making them highly vulnerable to radiation damage. - Any unrepaired DNA damage will be transmitted to both daughter cells during the upcoming mitosis.
Question 6: In which type of lung carcinoma is the p53 mutation most commonly observed?
- A. Adenocarcinoma
- B. Squamous cell carcinoma (SCC) (Correct Answer)
- C. Large cell carcinoma
- D. Small cell carcinoma
Explanation: ***Small cell carcinoma*** - **Small cell lung carcinoma (SCLC)** has the highest frequency of **p53 mutations**, occurring in approximately **90-95%** of cases. - These mutations are associated with the **aggressive nature** and **poor prognosis** of SCLC, contributing to its rapid growth and early metastasis. *Adenocarcinoma* - **Adenocarcinoma** has p53 mutations in approximately **50-60%** of cases, which is less frequent than SCLC. - This subtype is more commonly associated with **EGFR mutations** and **ALK rearrangements**, particularly in non-smokers. *Squamous cell carcinoma (SCC)* - **Squamous cell carcinoma** shows p53 mutations in about **70-80%** of cases, but still lower than SCLC. - It is more strongly associated with **smoking** and often displays mutations in **CDKN2A** and **PIK3CA** pathways. *Large cell carcinoma* - **Large cell carcinoma** has variable p53 mutation rates, typically **40-60%** of cases. - This subtype is less well-characterized molecularly and represents a **diagnosis of exclusion** among lung cancers.
Question 7: Which of the following is not an apoptotic gene?
- A. Mcl-1
- B. Bax
- C. P53
- D. n-myc (oncogene) (Correct Answer)
Explanation: ***n-myc*** - **n-myc** is primarily known for its role in **cell proliferation and differentiation**, not specifically associated with apoptosis [2]. - It is an **oncogene** that can contribute to tumorigenesis, but does not directly regulate apoptotic pathways [3]. *P53* - **P53** is a well-known **tumor suppressor gene** that plays a crucial role in inducing apoptosis in response to DNA damage [1]. - Activation of P53 leads to the transcription of genes that promote cell death, thus it is definitely an apoptotic gene [1]. *Bax* - **Bax** is a pro-apoptotic member of the **Bcl-2 family**, promoting apoptosis by facilitating mitochondrial outer membrane permeabilization [4,5]. - It plays a direct role in the apoptotic pathway, making it an important apoptotic gene [5]. *Mcl-1* - **Mcl-1** is an anti-apoptotic member of the **Bcl-2 family**, which helps prevent apoptosis by inhibiting pro-apoptotic factors [2,3]. - Its function is to **promote cell survival**, not apoptosis, but it is still classified as part of the apoptotic regulatory network [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 303-304. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 310. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 310-311. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 65-67. [5] 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. 80-81.
Question 8: Intraoperative radiation therapy (IORT) is most commonly used in which of the following cancers?
- A. Ca Thyroid
- B. Ca Pancreas (Correct Answer)
- C. Ca Cervix
- D. Ca Breast
Explanation: ***Ca Pancreas*** - **Intraoperative radiation therapy (IORT)** is frequently employed for **pancreatic cancer** due to its deep-seated location and locally advanced nature at presentation. - IORT allows for a **high dose of radiation** (10-20 Gy) to be delivered directly to the tumor bed and involved lymph nodes at the time of surgery, while critical structures like the stomach, duodenum, and kidneys can be retracted or shielded. - Particularly useful in **borderline resectable or locally advanced cases** where complete resection margins are difficult to achieve. - Used in specialized centers as part of multimodal therapy to improve local control. *Ca Thyroid* - **Thyroid cancer** is generally treated with surgery (thyroidectomy) followed by **radioactive iodine (RAI) therapy** for papillary and follicular types, not typically IORT. - The thyroid gland's superficial location and high avidity for iodine make RAI an effective targeted therapy. - IORT has no established role in standard thyroid cancer management. *Ca Cervix* - **Cervical cancer** treatment involves surgery, **external beam radiation therapy (EBRT)**, and **brachytherapy**, which places radioactive sources directly into or near the tumor. - Brachytherapy is superior for cervical cancer due to excellent dose distribution to the cervix and parametrium. - IORT is not a standard approach for primary cervical cancer, though it might be considered in select recurrent cases. *Ca Breast* - For **breast cancer**, IORT has gained significant traction, particularly for **early-stage disease** (T1-T2, node-negative) as an alternative to 5-6 weeks of external beam radiation. - **TARGIT-A and ELIOT trials** have established IORT as a viable option for partial breast irradiation during breast-conserving surgery. - While increasingly used globally with dedicated devices (INTRABEAM, ELIOT), it remains a **selective option** rather than universally applied. - The indication is more specific (favorable early-stage tumors) compared to the broader applications in pancreatic cancer where dose escalation and organ sparing are critical challenges.
Question 9: What is the definition of a sentinel lymph node?
- A. The primary lymph node draining the tumor. (Correct Answer)
- B. The first lymph node excised during a modified radical mastectomy.
- C. The lymph node located nearest to the tumor.
- D. None of the above.
Explanation: ### Explanation **Concept Overview** The **Sentinel Lymph Node (SLN)** is defined as the first lymph node (or group of nodes) in a regional lymphatic basin that receives direct lymphatic drainage from a primary tumor. The underlying physiological principle is that lymphatic metastasis occurs in an orderly, step-wise fashion. If the sentinel node is negative for malignancy, there is a high probability (usually >95%) that the remaining nodes in that basin are also free of disease. **Analysis of Options** * **Option A (Correct):** This aligns with the physiological definition. It is the "gatekeeper" node. If the tumor spreads via lymphatics, this node is the first site of metastasis. * **Option B (Incorrect):** A Modified Radical Mastectomy (MRM) involves a formal axillary lymph node dissection (Levels I and II). The nodes removed are based on anatomical boundaries, not necessarily the specific drainage pattern of the tumor. * **Option C (Incorrect):** Proximity does not always equal drainage. Due to the complexity of lymphatic channels, the sentinel node may sometimes be anatomically distant from the tumor while still being the first node to receive its drainage. **Clinical Pearls for NEET-PG** * **Identification:** SLN is identified using **Isosulfan blue/Methylene blue dye** (visualized) and/or **Technetium-99m labeled sulfur colloid** (detected via a gamma probe). * **Most Common Indications:** Breast cancer (T1/T2 lesions) and Malignant Melanoma. * **Skip Metastasis:** This refers to a phenomenon where the SLN is negative, but higher-level nodes are positive. While rare, it is a limitation of SLN biopsy. * **Contraindications in Breast Cancer:** Inflammatory breast cancer, multicentric tumors (relative), and clinically palpable axillary nodes (N1/N2).
Question 10: What is the definition of neoadjuvant chemotherapy?
- A. Chemotherapy administered concurrently with surgery
- B. Chemotherapy administered prior to surgery (Correct Answer)
- C. Chemotherapy administered following surgery
- D. Chemotherapy administered in conjunction with radiation therapy
Explanation: **Explanation:** **Neoadjuvant chemotherapy** refers to the administration of systemic cytotoxic agents **prior to the primary definitive treatment** (usually surgery). The primary goal is to downstage the tumor, increase the likelihood of a complete (R0) resection, and treat micrometastatic disease early. * **Why Option B is Correct:** The prefix "neo-" (new/before) and "adjuvant" (assisting) signifies therapy given before the main intervention. By shrinking the primary tumor, it can convert an inoperable case into an operable one or allow for breast-conserving surgery instead of a mastectomy. * **Why Options A, C, and D are Incorrect:** * **Option A:** Chemotherapy is rarely given *during* the surgical procedure itself (except for specialized techniques like HIPEC). * **Option C:** This describes **Adjuvant Chemotherapy**, which is given *after* surgery to eliminate residual microscopic disease and reduce recurrence risk. * **Option D:** This describes **Concurrent Chemoradiotherapy (CCRT)**, often used as definitive treatment in cancers like Carcinoma Cervix or Esophagus. **NEET-PG High-Yield Pearls:** 1. **Pathological Complete Response (pCR):** The gold standard for measuring the effectiveness of neoadjuvant therapy; it implies no viable tumor cells remain in the surgical specimen. 2. **Common Indications:** Locally advanced breast cancer (LABC), esophageal cancer, and rectal cancer (often as neoadjuvant chemoradiation). 3. **Window of Opportunity:** It provides an *in vivo* assessment of how sensitive the tumor is to a specific chemotherapy regimen.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free