Further, we established stable matriptase knockdown in two MM cell lines with high matriptase gene expression; RPMI-8226 (RPMI-8226 shMatriptase) and JJN-3 (JJN-3 shMatriptase), and respective control cells (RPMI-8226 shMock and JJN-3 shMock). This evidence concerns the gene ST14 and Miyoshi myopathy.