SPINK4 and colorectal carcinoma: To examine the levels of SPINK4 mRNA in CRC samples, we first analyzed SPINK4 mRNA expression by comparing 17 CRC tissues and paired adjacent normal tissues from the GSE32323 dataset, and the results indicated that the relative SPINK4 expression level was significantly decreased in CRC tissues compared with that in adjacent normal tissues (8.5 ± 2.2 vs. 10.5 ± 2.6, P = 0.016, Fig. 2a).