NRAS Mutation Analysis with Interpretation
Order Code: NRAS
Epic Lab Code: LAB7662
Order Form: A-1a Miscellaneous Request or Epic Req
Molecular Pathology
6004 BT GH
384-9568
Specimen(s):
Formalin Fixed, Paraffin Embedded Tissue
10 unstained 5-10 μM section glass slides at 20-25°C and an H&E slide or the tissue block.
Minimum:
Tumor cells more than 50% of the total tissue and greater than 10mm2 in surface area on the block.
Rejection Criteria:
Specimens fixed in B5 fixative or that have been decalcified will not be accepted. Tumor specimens containing less than 50% tumor cells or are less than 10mm2 in area may be unacceptable.
Testing Schedule:
Weekly
Turn Around Time:
7-10 working days
Reference Range:
Negative for mutations (normal).
Interpretive Data:
The presence of an oncogenic mutation in codons 12, 13, or 61 of NRAS is indicative of a tumor that may respond to drugs targeted at genes downstream of NRAS in the mitogen activating protein kinase (MAPK) signaling cascade, as in malignant melanoma cases. In contrast, mutations in NRAS can inhibit therapeutic response to EGFR-targeted therapies in patients with metastatic colorectal cancer.

NRAS mutations are found in the more aggressive variant of chronic myelogenous leukemia (CMML) and may predict response to farnesyl transferase inhibitors therapy in acute myeloid leukemia (AML).
Comments:
The tissue should be reviewed by a pathologist prior to testing to identify that it contains at least 50% tumor.

This assay detects mutations in codons 12, 13 and 61 (20 mutations in total).
Test Limitations:
Mutations in other locations within the NRAS gene or in any other gene will not be detected.

Absence of NRAS mutations does not guarantee a positive response to anti-EGFR therapies in metastatic colorectal cancer.

The presence of mutations in codons 12, 13, or 61 does not guarantee a positive response to therapies in melanoma.
Methodology:
Polymerase Chain Reaction and Single Nucleotide Primer Extension
CPT Code:
81404