Furthermore, we compared the frequency of KRAS, BRAF and PIK3CA mutations found in polyps with the frequency found in a series of 103 sporadic colorectal tumours, 50 MSI CRC and 53 MSS CRC, in order to understand the importance of these oncogenic events for the progression of the various types of colorectal cancer. The gene discussed is PIK3CA; the disease is colorectal carcinoma.