MMP9 and lung cancer: Surfactin induces apoptosis in MCF-7 human breast cancer cells through a ROS/JNK-mediated mitochondrial/caspase pathway (Cao et al. 2010), suppresses TPA-induced breast cancer cell invasion through the inhibition of MMP-9 expression (Park et al. 2013a), and inhibits the growth of the human lung cancer cell line 95D through reactive oxygen species production and mitochondria-dependent apoptosis (Yin et al. 2013).