CCND1 and cancer: Subgroup analysis according to cancer types presented significant association of CCND1 polymorphism and increased breast cancer risk in dominant model (GG vs GA+AA: OR = 2.75, 95%CI = 1.54–4.90, P=0.0006) and allelic model (G vs A: OR = 1.63, 95%CI = 1.22–2.19, P=0.001).