Vitamins and minerals: all-trans retinoic acid in promyelocytic leukaemia: practice question

A Biochemistry 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.

Try it

Biochemistry · Vitamins and minerals: all-trans retinoic acid in promyelocytic leukaemia

Sample item

A 30-year-old has bleeding, pancytopenia and a prolonged prothrombin time. Marrow shows abnormal promyelocytes with Auer rods and t(15;17). A vitamin A derivative is added to chemotherapy. How does it act?

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

The answer and the reasoning

C. It binds the PML-RARA fusion protein and triggers promyelocyte maturation

t(15;17) fuses PML to the retinoic acid receptor alpha gene. The fusion protein blocks differentiation at the promyelocyte stage, and pharmacological doses of all-trans retinoic acid overcome the block and drive maturation. Arsenic trioxide also targets the fusion protein.

Option by option

  • A. It depletes extracellular asparagine and starves the leukaemic blasts

    Asparagine depletion is the action of asparaginase in lymphoblastic leukaemia.

  • B. It inhibits topoisomerase II and causes double-strand DNA breaks in blasts

    Topoisomerase II inhibition is the action of agents such as etoposide and anthracyclines.

  • C. It binds the PML-RARA fusion protein and triggers promyelocyte maturation (correct)

    Correct. Retinoic acid acts on the PML-RARA receptor to restore differentiation.

  • D. It blocks BCR-ABL tyrosine kinase signalling in the leukaemic cells

    BCR-ABL inhibition is the action of imatinib in chronic myeloid leukaemia.

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 Biochemistry questions

Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is C, It binds the PML-RARA fusion protein and triggers promyelocyte maturation. t(15;17) fuses PML to the retinoic acid receptor alpha gene.

Why is "It depletes extracellular asparagine and starves the leukaemic blasts" not the answer?

Asparagine depletion is the action of asparaginase in lymphoblastic leukaemia.

Why is "It inhibits topoisomerase II and causes double-strand DNA breaks in b…" not the answer?

Topoisomerase II inhibition is the action of agents such as etoposide and anthracyclines.

Why is "It blocks BCR-ABL tyrosine kinase signalling in the leukaemic cells" not the answer?

BCR-ABL inhibition is the action of imatinib in chronic myeloid leukaemia.

What concept does this question test?

It tests Vitamins and minerals: all-trans retinoic acid in promyelocytic leukaemia in Biochemistry. The fusion protein blocks differentiation at the promyelocyte stage, and pharmacological doses of all-trans retinoic acid overcome the block and drive maturation. Arsenic trioxide also targets the fusion protein.

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 Vitamins and minerals: all-trans retinoic acid in promyelocytic leukaemia?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry 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.