Neoplasia: predictive molecular markers in lung cancer: 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: predictive molecular markers in lung cancer

Sample item

A 50-year-old non-smoking woman has stage IV lung adenocarcinoma. Which molecular finding best predicts a response to the tyrosine kinase inhibitors erlotinib or gefitinib?

AActivating EGFR mutation such as an exon 19 deletionBALK gene rearrangementCHigh PD-L1 expressionDKRAS codon 12 mutation

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

The answer and the reasoning

A. Activating EGFR mutation such as an exon 19 deletion

Activating EGFR mutations, commonly exon 19 deletions or the L858R point mutation, are more frequent in never-smokers, women and Asian patients, and predict sensitivity to EGFR tyrosine kinase inhibitors. All patients with advanced lung adenocarcinoma should have molecular testing.

Option by option

A. Activating EGFR mutation such as an exon 19 deletion (correct)
EGFR activating mutations confer sensitivity to EGFR inhibitors.
B. ALK gene rearrangement
ALK rearrangement predicts response to ALK inhibitors such as crizotinib, not EGFR inhibitors.
C. High PD-L1 expression
High PD-L1 expression predicts benefit from immune checkpoint inhibitors.
D. KRAS codon 12 mutation
KRAS mutation is mutually exclusive with EGFR mutation and is associated with resistance to EGFR inhibitors.

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.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is A, Activating EGFR mutation such as an exon 19 deletion. Activating EGFR mutations, commonly exon 19 deletions or the L858R point mutation, are more frequent in never-smokers, women and Asian patients, and predict sensitivity to EGFR tyrosine kinase inhibitors.

Why is "ALK gene rearrangement" not the answer?

ALK rearrangement predicts response to ALK inhibitors such as crizotinib, not EGFR inhibitors.

Why is "High PD-L1 expression" not the answer?

High PD-L1 expression predicts benefit from immune checkpoint inhibitors.

Why is "KRAS codon 12 mutation" not the answer?

KRAS mutation is mutually exclusive with EGFR mutation and is associated with resistance to EGFR inhibitors.

What concept does this question test?

It tests Neoplasia: predictive molecular markers in lung cancer in Pathology. All patients with advanced lung adenocarcinoma should have molecular testing.

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: predictive molecular markers in lung cancer?

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.