Considering the wide divergence in the frequency of KRAS and BRAF mutations in the precursor lesions of CRC and the absence of data in the Chinese population, the aims of this study are to investigate the frequency of KRAS and BRAF mutations in precursor lesions of colorectal cancer in a Chinese population and to study the association between molecular alterations and histologic features. This evidence concerns the gene KRAS and colorectal carcinoma.