STAT3 and AL amyloidosis: For example, the V protein of Mumps virus (MuV) catalyzes proteasomal degradation of STAT1 and STAT3, resulting in blockade of IFN-I, IFN-II, and prevention of the responses to interleukin-6 and v-Src signals and induction of apoptosis in STAT3-dependent multiple myeloma cells and transformed murine fibroblasts (101).