BRAF and signet ring cell carcinoma: Analysis with respect to histology showed that the frequencies of poorly differentiated adenocarcinoma (por), mucinous carcinoma (muc) and signet-ring cell carcinoma (sig) were <10.9% in patients with wt BRAF, which supported previous reports that such histologies are rare in CRC (Ogino et al, 2006; Catalano et al, 2009).