CCND1 and lip and oral cavity carcinoma: The overall data did not demonstrate any association of CCND1 polymorphism with oral cancer risk (AA vs. GG: OR=1.06; 95% CI, 0.62–1.82; P=0.002 for heterogeneity; dominant model: OR=1.04; 95% CI, 0.76–1.43; P=0.08 for heterogeneity; recessive model: OR=1.06; 95% CI, 0.70–1.59; P=0.006 for heterogeneity; Figs. 1–3).