IDO1 and Miyoshi myopathy: As shown in Figure 7A, WP1066, a potent STAT3 inhibitor, down-regulated STAT3 phosphorylation as well as IDO protein expression in MOLP-8 MM cells, but not in U266 MM cells, suggesting that HGF may be implicated in IDO regulation through multiple signaling pathways, at least in some MM cases.