Gelatinase B/MMP-9 cooperates with Snail transcription factor to induce EMT in epidermoid carcinoma cells [231], is involved in medulloblastoma cell EMT [232], is induced by Twist transcription factor an essential inducer of EMT [233,234,235] and by krupple like factor (KLF)-8, a critical component of FAK-regulated breast cancer EMT, which induces gelatinase B/MMP-9 expression in human breast cancer cells, promoting migration, invasion, angiogenesis and metastasis [234,235,236]. This evidence concerns the gene PTK2 and breast cancer.