SERPINB5 and lip and oral cavity carcinoma: In addition, gene-gene interaction to increase oral cancer susceptibility was also found among participants with AG or GG of rs1455555 A/G, CT or TT of rs2289519 C/T, and GC or GG of rs2289520 G/C polymorphisms of Maspin. Jang et al. [16] identified a C526T Maspin polymorphism in exon 5 from cDNA samples using human cancer cells, which resulted in an amino acid substitution of Ser for Pro at amino acid 176 of Maspin protein.