FAS and AL amyloidosis: Atsuta et al. found that when MSCs interacted with multiple myeloma (MM) cells, tumor cell proliferation was inhibited through Fas-mediated apoptosis (Fas and Fas-L are co-synthesized on MSCs, which, when co-cultivated, can reduce the proliferation of MM cells), and apoptosis was induced due to the activation of CASP3 and CASP8 [60].