Indeed, our results showed an upregulation of let-7e-5p in CRC tissues with mutation in KRAS codon 12 or 13 and, for the first time, suggested an association between let-7a-5p, let-7b-5p, let-7c-5p, let-7d-5p, and let-7i-5p and perineural invasion in CRC. This evidence concerns the gene KRAS and colorectal carcinoma.