MMP9 and breast cancer: Univariate analysis showed that serum TGF- β 1, MMP-9 and IL-1 β were influencing factors of BC (p < 0.05), while multivariate analysis showed that high level of serum TGF- β 1 and MMP-9 were independent risk factors of BC (p < 0.05), serum IL-1 β was not an independent risk factor for BC (p > 0.05).