MMP13 and malignant colon neoplasm: The aim of this study was to investigate association of polymorphisms rs1799750 in MMP-1, rs243865 in MMP-2, rs11568818 in MMP-7, rs2252070 in MMP-13 and rs28366003 in MT2A, together with serum Zn level, with occurrence of breast, lung and colon cancer in Poland.