CD274 and cervical carcinoma: Therefore, we explored the effect of RA on the expression of PD-L1 in HeLa cells, and we found that the gene and protein expression of PD-L1 in HeLa cells treated with RA decreased compared with the controls, which indicated that RA can inhibit HeLa cervical cancer cells via reducing the expression of PD-L1 and RA can be one of the potential immunotherapies for HPV-related tumors.