Manual click here search of references cited in the published studies did not reveal any additional articles. As a result, a total of seven relevant studies met the inclusion criteria for the meta-analysis [11–15,
18, 19]. Among them, one of the eligible studies contained data on two different ethnic groups , and we treated it independently. Therefore, a total of eight separate comparisons including 2069 endometrial cancer cases and 4546 controls were finally included in our meta-analysis. The main characteristics of the studies are presented CCI-779 cell line in Table 1. Of all the eligible studies, six were conducted in Caucasian populations, and two were in Asians. Four studies were population–based and four were hospital–based studies. All studies used validated methods including PCR-RFLP, TaqMan assay to genotype the MDM2 SNP309 polymorphism. The endometrial cancer cases were histologically or pathologically confirmed in five of the eligible studies. The genotype distribution of the controls in one study was not consistent with HWE . Table 1 Characteristics of studies included in this meta-analysis First author (Year) Country Ethnicity Sample size (case/control) Genotyping
methods Matching criteria Source of control EC confirmation Quality scores HWE (P value) Walsh EGFR inhibitor  America Caucasian 73/79 PCR-RFLP NA HB NA 5.5 0.650 Terry NHS  America Caucasian 394/948 PCR-RFLP Age, menopausal status PB PC 11 0.642 Terry WHS  America Caucasian 122/368 PCR-RFLP Age, menopausal status PB PC 11 0.180 Ashton 2009  Australia Caucasian 191/291 TaqMan Assay Age, gender PB HC 9 0.493 Nunobiki  Japan
Asian 102/95 PCR-RFLP NA HB HC 5 0.018 Zajac  Poland Caucasian 152/100 PCR-RFLP NA HB HC 6.25 0.701 Knappskog  Norway Caucasian Farnesyltransferase 910/2465 TaqMan Assay NA HB NA 8 0.406 Yoneda  Japan Asian 125/200 PCR-RFLP NA PB NA 9 0.910 EC, Endometrial cancer; HC, Histologically confirmed; PC, Pathologically confirmed; NA, Not available; PB, Population–based; HB, Hospital–based; HWE, Hardy–Weinberg equilibrium in control population; PCR–RFLP, Polymerase chain reaction-restriction fragment length polymorphism. Meta-analysis The results of the association between MDM2 SNP309 polymorphism and endometrial cancer risk were shown in Table 2. Overall, significant elevated endometrial cancer risk was found when all studies were pooled into the meta-analysis (GG vs. TT: OR = 1.464, 95% CI 1.246–1.721, P < 0.001, Figure 1; GG vs. TG + TT: OR = 1.726, 95% CI 1.251–2.380, P = 0.001; GG + TG vs. TT: OR = 1.169, 95% CI 1.048–1.304, P = 0.005). In subgroup analysis by ethnicity, significant increased endometrial cancer risk was found in Caucasians (GG vs. TT: OR = 1.602, 95% CI 1.208–2.125, P = 0.001; GG vs. TG + TT: OR = 1.748, 95% CI 1.161–2.632, P = 0.007; GG + TG vs. TT: OR = 1.173, 95% CI 1.047–1.315, P = 0.006) but not in Asians.