Overall, the pooled analysis indicated that COX-2 expression was significantly associated with susceptibility (Caucasians, OR = 3.94, 95% CI = 2.17-7.17, <i>P</i> < 0.05; Asians, OR = 20.51, 95% CI = 8.54-49.26, <i>P</i> < 0.05), cancer stage (OR = 3.01, 95% CI = 1.95-4.67, <i>P</i> < 0.05), myometrial invasion (OR = 1.59, 95% CI = 1.17-2.15, <i>P</i> < 0.05), lymph node metastasis (OR = 1.63, 95% CI = 1.18-2.26, <i>P</i> < 0.05), and prognosis (OR = 2.91, 95% CI = 1.17-4.66, <i>P</i> < 0.05) in endometrial cancer. This evidence concerns the gene PTGS2 and cancer.