Definition

NRAS encodes a GTPase protein from the same RAS family as KRAS; activating mutations at codons 12, 13 and 61 make the EGFR signaling pathway independent, similar to KRAS mutations. In colorectal cancer, NRAS mutations are rarer than KRAS (3-5%) but have similar clinical effects (anti-EGFR resistance).

Gene/region examined

NRAS Codon 12, NRAS Codon 13, NRAS Codon 59, NRAS Codon 61, NRAS Codon 117, NRAS Codon 146

Method

DNA analysis

Accepted sample types

Fresh tumor tissue, FFPE

Description

Response to drug therapy.

Inheritance

Somatic; as with KRAS, it is acquired in tumor tissue and is not hereditary.

Related Tests

Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

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Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

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VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

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How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

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Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

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