Personalized cancer treatment is just around the corner, suggests a new study. Using SNaPshot, a “multiplexed, robust, highly sensitive and quick clinical test,” Lecia Sequist, Dora Dias-Santagata and colleagues at Massachusetts General Hospital have screened patients with non-small-cell lung cancer (NSCLC) for multiple cancer-causing gene mutations and demonstrated that implementing broad genotyping in routine clinical practice can identify the right type of treatment for the right patients. “Because each tumor harbor[s] a specific set of mutations, [this] test allows us to match individual[s] with the therapies that will most likely be effective in treating their cancer,” Dias-Santagata explains.
The SNaPshot test can identify over 50 mutation sites in 14 key cancer genes within 2–3 weeks. Out of 552 patients with NSCLC who underwent genotyping, 282 (51%) had at least one mutation or genetic rearrangement in the tested gene loci. The most common mutation sites were identified in KRAS (24%), EGFR (13%), ALK (5%), PIK3CA (4%), BRAF (2%) and HER2 (1%), for which targeted therapies are either available or forthcoming. In fact, 170 patients with advanced-stage disease, or who recurred during the follow up, had a 'potentially targetable' genotype, and 38% of these enrolled in at least one clinical trial of a targeted therapy.
Patients' survival was also affected by their genotype; mutations in KRAS reduced survival, whereas mutations in EGFR improved survival compared with wild-type genes. Interestingly, EGFR or KRAS mutations were associated with adenocarcinoma, whereas PIK3CA mutations mostly occurred in squamous cell cancers. Aberrations in EGFR and ALK were associated with low smoking levels, whereas KRAS mutations mostly occurred in heavy smokers.
This group have now expanded SNaPshot genotyping to colorectal, brain and breast cancers. “[We aim] to be on the leading edge of the progress toward expanding the scope and breadth of genotype-specific treatments,” Sequist says.
ORIGINAL RESEARCH PAPER
Sequist, L. V. et al. Implementing multiplexed genotyping of non-small-cell lung cancers into routine clinical practice. Ann. Oncol. doi:10.1093/annonc/mdr489
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Ozerlat, I. Smile, they're taking a SNaPshot of your cancer-causing genes. Nat Rev Clin Oncol 9, 6 (2012). https://doi.org/10.1038/nrclinonc.2011.184