**6. Conclusions**

A major challenge in cancer biology and cancer therapy relies in the availability of suitable models that recapitulate the complex tumor-host interplay and responsiveness to drugs. This is especially true for MM, where the existence of tight links between MM cells and BM micro‐ environment has hampered for long the development of adequate animals and *in vitro* mod‐ els. Recently, innovative murine and chimeric *in vivo* models have been developed, which allowed both to investigate MM physiopathology and to perform drugs testing. On the other hand, the exploitation of novel technologies for *ex-vivo* 3D culturing of human MM samples is emerging as a tool to properly investigate its pathogenetic mechanisms (and interactions) within a human context, and also to predict response to drugs in individual patients.

The availability of more and more sophisticated systems is expected to pave the way to a deeper understanding of pathogenetic events and also to development of novel patients-tail‐ ored therapeutic strategies.
