PIK3CA and neoplasm: In confirmation of previous reports, K-Ras and B-Raf mutations were mutually exclusive in our tumour series (Yuen et al, 2002; Suehiro et al, 2008), whereas mutations in K-Ras and PIK3CA, in and B-Raf and PIK3CA were found together, but occurred in only 7.8 and 2.9% of tumours, respectively.