Use of aspirin in colorectal cancer has previously been associated with favorable outcome. In a current study in the New England Journal of Medicine, Liao et al. report that 5-year cancer-related mortality was reduced by about 80% with regular use of aspirin when patients’ tumors had mutations in the PIK3CA gene.
Overall survival was also significantly improved in the mutation-positive group that used aspirin. Aspirin did not have a protective effect against unmutated tumors. Mutations in PIK3CA are detected in the tumors of approximately 20% of patients with colon cancer.
Although further confirmation is needed, the current findings suggest that PIK3CA mutation analysis is an appropriate companion test and predictive biomarker for adjuvant aspirin treatment in colorectal cancer.
PIK3CA Mutation Analysis is available from NeoGenomics, Fort Myers, Fla. The test is comprehensive and based on the gold standard bidirectional sequencing of PIK3CA exons 1, 9, and 20, which represent the critical domain of the gene, according to the company. The test covers both exons analyzed in the NEJM article by Liao et al. (exons 9 and 20).
PIK3CA testing can be ordered individually or as part of the NeoTYPE™ Colorectal Cancer Profile, which also includes MSI, BRAF, KRAS, TP53, and six other genes significant in solid tumors.
Specimen Requirements for PIK3CA Mutation Analysis:
- FFPE solid tumor tissue: 1 H&E slide, plus paraffin block or 5-10 unstained slides cut at 5 or more microns. Please use positively-charged slides and 10% NBF fixative. Do not use zinc fixatives.
- Tech-only microdissection: Optional. To participate, send the H&E slide with area of interest circled, along with block or cut slides as above. Try to enrich to at least 40% tumor within the circle. Mark on the slide or requisition the estimated percentage tumor in the circle (required).
Turnaround Time: 7 days
Click here to view printable specimen requirements, CPT codes, and other details. Mutation analysis, the NeoTYPE™ Profile, and tech-only microdissection can be ordered on the Solid Tumor Requisition.
Reference: Liao X, Lochhead P, Nishihara R, et al. Aspirin use, tumor PIK3CA mutation, and colorectal-cancer survival. N Engl J Med. 2012;367(17):1596-1606.