1721 C > G (rs2250889) MMP9, there were previously seven publications (four experimental [17,55,59,60] and three meta-analyses [8,57,58]) and only in two of them (experimental [17] and meta-analysis [58]) associations of this polymorphism with the disease are shown (the G allele increased the BC risk; in our work, the opposite results were obtained; this allele has a protective effect for BCin obese women). The gene discussed is MMP9; the disease is breast cancer.