Which of the following genetic alteration is commonly found in melanomas and is associated with increased cell proliferation and survival?

Appeared in: MP NHM CHO-2024 (Shift-2)

Explanation

NRAS is a proto-oncogene frequently mutated in approximately 20% of melanomas, making it a common genetic alteration.
It is a key component of the Mitogen-Activated Protein (MAP) kinase signaling pathway, which is central to regulating cell growth.
Activating mutations in NRAS cause the MAP kinase pathway to be constantly 'on,' which directly drives uncontrolled cell proliferation and enhances cell survival, contributing to tumor growth.

Option A: Mutations in the IDH1 gene are characteristic of other cancers, primarily gliomas and acute myeloid leukemia (AML), and are not a common finding in melanoma.
Option B: PTEN is a tumor suppressor gene, not an oncogene. Its loss of function (through deletion or silencing) contributes to melanoma by activating the PI3K/AKT pathway, but NRAS is the classic activating oncogene in the MAP kinase pathway as described in the question.
Option D: RET gene mutations are hallmark genetic events in medullary thyroid carcinoma and are associated with Multiple Endocrine Neoplasia (MEN) syndromes, not cutaneous melanoma.

Visual 1: Diagram - A simplified diagram of the MAP kinase (RAS-RAF-MEK-ERK) signaling pathway. This visual should highlight the position of NRAS and BRAF to show how their mutation leads to constant downstream signaling for cell proliferation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Genetic mutations driving melanoma pathogenesis as background academic context rather than a clinical decision trigger.
Identifying specific driver mutations like NRAS or BRAF is crucial for guiding targeted therapy in advanced melanoma. A nurse should understand that a patient's mutational status dictates the specific chemotherapy or immunotherapy regimen.
Nurses play a key role in educating patients about their diagnosis, including the significance of genetic test results and how they influence the treatment plan.
What if? If the patient's melanoma tested positive for a BRAF V600E mutation instead of NRAS, the first-line treatment would likely be a combination of a BRAF inhibitor (e.g., dabrafenib) and a MEK inhibitor (e.g., trametinib), a different therapeutic approach than for NRAS-mutant tumors.

How to Approach the Question

This is a factual recall question testing knowledge of molecular oncology.
First, identify the core subject: genetic alterations in melanoma.
Next, analyze the function described: 'increased cell proliferation and survival.' This points towards an activating mutation in an oncogene.
Evaluate each option by recalling the primary cancer type associated with each gene mutation.
NRAS is a well-known oncogene in the RAS family, a classic driver of cell proliferation pathways in many cancers, including melanoma.
Eliminate the other options based on their function (PTEN is a tumor suppressor) or their association with different cancers (IDH1 with gliomas, RET with thyroid cancer).

Concept Tested & Keywords

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Practise the full MP NHM CHO-2024 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.