Bi-directional sequencing of NRAS exon 4 is performed using PCR primers designed to target hotspot mutations in codons 117 and 146, among other regions in exon 4. Testing is available separately or in combination with BRAF, KRAS and HRAS in the RAS/RAF Panel. Testing is approved for specimens from the state of New York.
NRAS is highly homologous with KRAS; both are members of the most frequently mutated family of oncogenes. NRAS Mutations are found in a wide variety of solid tumors, in advanced systemic mastocytosis, and in myeloid neoplasias. Mutations in codon 117 and 146 are also believed to have similar effects as other mutations in RAS that involve exons 2 and 3. Patients with any known KRAS mutation or NRAS mutation may be resistant to certain tyrosine kinase inhibitors.
FFPE tissue: Paraffin block is preferred. Alternatively, send 1 H&E slide plus 5-10 unstained slides cut at 5 or more microns. Please use positively-charged slides and 10% NBF fixative. Do not use zinc fixatives.
Use cold pack for transport, making sure cold pack is not in direct contact with specimen. All slides can be packed at room temperature.