BMP4 and neoplasm: Tumor volume was assessed 2 weeks after MSC1 implantation (Figure 6c), demonstrating that MSC1‐BMP4 significantly reduced tumor size compared to MSC1‐NP controls during the early phase of recurrence (Figure 6d) consistent with the in vitro results demonstrating reduced proliferation (Figure 3c,g) and enhanced differentiation (Figure 4h,i).