Due to the recent easy access to next generation sequencing, we sought to analyze a small discovery cohort of 100 PTC and 100 CRC samples using exome sequencing to identify MAP2K1 mutations and their correlation to other MAPK pathway mutations, especially since recent reports have shown mutual exclusivity between MAP2K1 mutations and BRAFV600E mutations in these organ sites (17, 21). The gene discussed is MAP2K1; the disease is colorectal carcinoma.