Neoplasia: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pathology · Neoplasia

Sample item

A child has bilateral retinoblastoma and the father had a childhood eye tumour. Which mechanism best explains this?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

D. Inherited mutation of one RB allele, with somatic loss of the second allele in retinal cells

Knudson's two-hit hypothesis holds that familial retinoblastoma children carry one defective RB allele in every cell, so only one further somatic hit is needed. This makes tumours likely, often multiple or bilateral, and raises the risk of second cancers such as osteosarcoma.

Option by option

  • A. Amplification of the N-myc oncogene in retinoblasts

    N-myc amplification is associated with neuroblastoma rather than retinoblastoma.

  • B. Loss of both RB alleles through two independent somatic hits in a single retinal cell

    Two somatic hits in one cell is the sporadic pattern, which is rare, usually unilateral and unifocal, and does not explain a family history.

  • C. Gain-of-function mutation of a proto-oncogene inherited from the father

    Retinoblastoma is driven by loss of a tumour suppressor, not by inherited oncogene activation.

  • D. Inherited mutation of one RB allele, with somatic loss of the second allele in retinal cells (correct)

    Correct. One inherited hit plus a single somatic hit explains early, bilateral, familial disease.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is D, Inherited mutation of one RB allele, with somatic loss of the second allele in retinal cells. Knudson's two-hit hypothesis holds that familial retinoblastoma children carry one defective RB allele in every cell, so only one further somatic hit is needed.

Why is "Amplification of the N-myc oncogene in retinoblasts" not the answer?

N-myc amplification is associated with neuroblastoma rather than retinoblastoma.

Why is "Loss of both RB alleles through two independent somatic hits in a sin…" not the answer?

Two somatic hits in one cell is the sporadic pattern, which is rare, usually unilateral and unifocal, and does not explain a family history.

Why is "Gain-of-function mutation of a proto-oncogene inherited from the fath…" not the answer?

Retinoblastoma is driven by loss of a tumour suppressor, not by inherited oncogene activation.

What concept does this question test?

It tests Neoplasia in Pathology. This makes tumours likely, often multiple or bilateral, and raises the risk of second cancers such as osteosarcoma.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neoplasia?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.