PDCD1 and cancer: Taken together, our findings from the meta-analysis of the correlation between analyzed polymorphisms and cancer susceptibility remained unchanged in the heterozygous (PD-1 rs2227982, PD-1 rs36084323 and PD-1 rs10204525), homozygous (PD-1 rs2227982, PD-1 rs7421861, PD-1 rs36084323, PD-1 rs10204525 and PD-L1 rs2890658), dominant (PD-1 rs36084323 and PD-1 rs10204525), recessive (PD-1 rs2227982, PD-1 rs7421861, PD-1 rs36084323 and PD-L1 rs2890658), and allele (PD-1 rs2227982, PD-1 rs7421861 PD-1 rs10204525 and PD-L1 rs2890658) genetic models (Figure 6).