The RT-PCR-based analysis of CK20, PLS3, LAD1, and DEFA5 expression in blood samples of 98 CRC and 64 IID patients as well as of 40 healthy donors revealed that PLS3 and LAD1 expression were detectable in almost all analyzed blood samples, while distinct differences in the detection rate of CK20 and DEFA5 could be determined in the three sub-cohorts, however, not allowing a more in-depth discrimination between CRC and IID patients. This evidence concerns the gene DEFA5 and colorectal carcinoma.