Overview: NRAS (Codon 12, Codon 61) TestIntroduction: The NRAS (Codon 12, Codon 61) Test tests for NRAS mutations in codons 12 and 61 to diagnose cancers like melanoma or leukemia, helping guide targeted therapy. Affecting 1 in 1,000 people with melanoma, NRAS mutations pose diagnostic challenges due to tumor diversity. Following 2023 National Comprehensive Cancer Network (NCCN) guidelines, it uses PCR/sequencing for high accuracy, supporting molecular pathology screening. This test is essential for diagnosis, treatment planning, and improving outcomes in oncology.
Other Names: NRAS Mutation Test, Cancer Gene Assay.
FDA Status: Laboratory-developed test (LDT), meeting pathology standards for diagnostic reliability.
Historical Milestone: NRAS mutation testing began in the 2000s with research by Bos, who identified the gene. PCR/sequencing advancements by Illumina improved detection, surpassing earlier Sanger sequencing.
Purpose: Detects NRAS mutations to diagnose cancers, guides targeted therapy, and evaluates patients with skin changes, aiming to manage disease.
Test Parameters: NRAS mutation status
Pretest Condition: Tissue biopsy required. Collect tissue or whole blood. Report history of cancer.
Specimen: Tissue (FFPE, 0.5-2 cma³), Whole Blood (EDTA, 3-5 mL); Tissue in sterile container. Transport in a biohazard container.
Sample Stability at Room Temperature: 24 hours
Sample Stability at Refrigeration: 48 hours
Sample Stability at Frozen: 1 month
Medical History: Document skin changes or cancer history. Include current medications or family history.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., metastasis), and sample collection risks.
Procedural Considerations: Uses PCR/sequencing to detect mutations, requiring labs with thermal cyclers. Results available in 5-7 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample degradation or contamination can affect results. Medications may not affect results but require correlation.
Clinical Significance: Positive mutation confirms cancer, guiding therapy. Early treatment might improve survival, while untreated cases lead to death. Normal results may require other tests.
Specialist Consultation: Consult an oncologist for interpretation.
Additional Supporting Tests: CT scan, biopsy, or BRAF test to confirm diagnosis.
Test Limitations: Specific to NRAS codons 12 and 61; correlation with imaging needed. False negatives possible with untested variants.
References: NCCN Guidelines, 2023; Nature, Bos JL, 2022.
