A simultaneous gene expression pattern of immune checkpoint molecules might exist in colorectal cancer. This hypothesis has rarely been tested in human in vivo samples.
We investigated the gene expression patterns of immune checkpoint molecules in human colorectal cancer tissues using quantitative polymerase chain reaction (qPCR) with a focus on concurrent gene expression.
We included 14 females and 16 males with a mean age was 68.5 years. The mean number of all immune checkpoint molecules did not differ significantly between normal and tumor tissues. Histological grade 3 tumors were more common in the PDCD1-expressing group [3 (25.0%) vs. 0 (0%) (p = 0.042)]. All six and four immune checkpoint molecules were expressed in eight and three PDCD1-positive patients, respectively. Specifically, CD274 was expressed in 11 of 12 PDCD1-positive patients, while LAG3 and IDO1 were expressed simultaneously in all patients expressing CD274.
Colorectal cancers more commonly express multiple immune checkpoint molecules simultaneously than single molecules. This suggests that blocking multiple immune checkpoint pathways may serve as a potential strategy for immunotherapy.