To gain insight into the effects of KLKs on the progression and prognosis of CRC, the present study investigated the expression profiles of KLKs in CRC using TCGA and GTEx databases and found that KLK1, KLK6, KLK8, KLK10, KLK11 and KLK12 were highly expressed in tumour tissues compared with normal tissues. This evidence concerns the gene KLK12 and colorectal carcinoma.