In conclusion, our data support a regulatory mechanism of PD-L1 expression on tumor cells and immune suppression via miR-148a-3p downregulation in colorectal cancer.
Restoring miR-148a expression prevented both spontaneous and carcinogen-induced colon tumor development. miR-148a was downregulated in human inflammatory bowel disease (IBD) and colorectal cancer patient tissues.
The down-regulation of miR-148a is implicated in invasion of gastric cancer, while high miR-21 expression in colorectal cancer is associated with poor survival.
Low expression of miR-148a was also correlated with increased tumor size (p = 0.045 and 0.018, respectively) in gastrointestinal cancers, but only correlated with advanced pT stage (p = 0.023) in colorectal cancer.