MMP2 and breast cancer: Muscle-invasive BC is associated with alterations of p53, retinoblastoma protein (RB1) and tumour suppressors controlling cell cycle processes, in addition to elevated expressions in epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2/ErbB2), matrix metallopeptidase 2 (MMP2) and MMP9 and deletions in p16Ink4a and P15Ink4b [3].