CD27 and Miyoshi myopathy: In the MM cell lines U266 and RPMI-8226, treatment with CD27 stimulators (sCD27 and 1F5) across 0 h, 24 h, 48 h, and 72 h intervals manifested a notable reduction in cell viability, especially with DMSO as a control, highlighting a time-dependent inhibition of MM cell growth (Fig. 4A, B).