Further experiments showed that overall PLCE1 mRNA expression was lower in tumor than in paired normal tissues (0.067±0.016 vs 0.264±0.067, P<.05), and the IHC analysis showed the normal tissues of rs2274223 GG genotype had a lower PLCE1 staining score than that of the AG genotype (0.40±0.22 vs 1.33±0.32, P<.05).
Although none of three SNPs was alone significantly associated with overall risk of SCCHN, their combined effects of risk alleles (rs2274223G, rs3203713G and rs11599672G) were found to be associated with risk of SCCHN in a locus-dose effect manner (Ptrend=0.046), particularly for non-oropharyngeal tumors (Ptrend=0.017); specifically, rs2274223 was associated with a significantly increased risk (AG vs. AA: adjusted OR=1.29, 95% CI=1.01-1.64; AG/GG vs. AA: adjusted OR=1.30, 95% CI=1.03-1.64), while rs11599672 was associated with a significantly decreased risk (GG vs. TT: adjusted OR=0.54, 95% CI=0.34-0.86; TG/GG vs. TT: adjusted OR=0.76, 95% CI=0.61-0.95).