MMP2 and breast cancer: Apart from this, chlorin e6 (Ce6), berberrubine (BBR) and matrix metalloproteinase-2 (MMP-2) response peptide (PLGVRKLVFF) were coupled by linkers to form a linear triblock molecule BBR-PLGVRKLVFF-Ce6 (BPC), which can self-assemble into nanoparticles for chemo-photodynamic therapy of breast cancer [406].