PROM1 and cancer: Sorted CD133− PaTu8988 cancer cells were cocultured with irradiated parental cancer cells (iHMGB1+ cells), irradiated HMGB1 knockdown cancer cells (HMGB1− cells), rhHMGB1 (150 ng/mL), or normal medium (control group) and then injected subcutaneously into nude mice for the indicated cell number (1 × 104, 1 × 105 and 1 × 106 cells/mouse were injected, respectively).