PROM1 and cancer: CD133 has been consistently reported to be a marker of chemo‐resistant cancer cells, which are enriched after treatment,22, 23, 24, 25, 26, 27 and CD133+ BTC cells were shown to be tumorigenic and express features of cancer stem cells (CSCs).9, 28 Therefore, we speculated that MIR1249 could affect chemo‐resistance by inducing the expansion of CD133+ BTC cells.