HTRA1 and colorectal carcinoma: To investigate the role of HTRA1 in CRC progression, we analyzed the expression of HTRA1 in Gene Expression Omnibus (GEO) datasets, including GSE41568, GSE83889 and GSE54986, and the abnormally elevated expression of HTRA1 was detected in CRC tissues compared with the normal intestinal mucosa (Fig. 1B).