As a result, the summary ORs remained unchanged, despite deleting one single study, the first studies, or deviations from HWE among controls, with the only exception of MMP-2 rs243865 with NPC risk among the Asian populations in dominant model, MMP-7 rs11568818 with CC risk in Asians under the dominant model, and MMP-9 rs3918242 with LC risk among the overall populations in the recessive model and with BC risk among the overall populations in the dominant model. This evidence concerns the gene MMP2 and breast cancer.