PTK2 and Miyoshi myopathy: We observed that (1): circ-PTK2 was expressed in MM cell lines (2); circ-PTK2 facilitated MM cell survival and migration but not cell invasion, and suppressed cell apoptosis (3); circ-PTK2 reversely regulated miR-638 and influenced MM cell activity, activated MEK&ERK and WNT&β-catenin signaling pathway via sponging miR-638.