Which of the following statements are correct about Retinoblastoma?

A. It is always unilateral

B. It is associated with increased risk of osteosarcoma

C. The RB protein is inactive (hypophosphorylated)

D. Oncogenesis occurs by loss of function mutation

E. The gene involved is called the 'guardian of the genome'

1. A

   B, D

2. B

   A, B, C, D

3. C

   C, D, E

4. D

   D, E

Appeared in: INI-CET EXAM -2025

Explanation

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• B, D matches the defining clue or classification criterion in the stem.
• Supporting mechanism: The option aligns with the governing rule, pattern, sequence, classification, or exam logic being tested.
• Key differentiator: It fits the one fact that separates the correct response from the closest distractor.

Why Other Options Were Wrong

• Option B: Statement A is incorrect because retinoblastoma is not always unilateral. While sporadic cases (~60%) are typically unilateral, hereditary cases (~40%) are often bilateral.
• Option C: Statement C incorrectly describes the activity of the RB protein. The RB protein is active when it is hypophosphorylated (under-phosphorylated), allowing it to bind to and inhibit the E2F transcription factor, thereby halting cell cycle progression. It is inactive when hyperphosphorylated.

Related Visual

• Visual 1: [object Object]
• Visual 2: [object Object]

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The genetic and clinical characteristics of Retinoblastoma and the function of the RB1 tumor suppressor gene as background academic context rather than a clinical decision trigger.
• [object Object].
• What if? - If the stem changed one defining clue so that B, D no longer matched, reassess the option whose mechanism, classification, or indication now fits the revised presentation.

How to Approach the Question

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Concept Tested & Keywords

• Concept Tested: The genetic and clinical characteristics of Retinoblastoma and the function of the RB1 tumor suppressor gene.
• Stem keywords: Retinoblastoma, unilateral, osteosarcoma, RB protein, hypophosphorylated, loss of function mutation, guardian of the genome
• Lead-in keywords: Which of the following statements are correct

Question ID

QYUwRd25oKcFnhWULUOiZb

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