While there was no significant between-group difference, an 8-week HIIT intervention significantly (within group differences) reduced MMP-9 levels in breast cancer patients undergoing anthracycline-based chemotherapy yet increased MMP-2 levels; no significant changes in MMP-1, -7, -10, TIMP-1 and TIMP-2 were observed. This evidence concerns the gene MMP2 and breast carcinoma.