FOLR1 and cancer: Furthermore, through FOLR1 knockdown experiments using shRNA, the authors demonstrated that the degradation of the NPM-ALK fusion by FA-S2-MS4048 was absent, reinforcing that the pro-PROTAC targets FOLR1-positive cancer cells, emphasizing the critical role of folate as a carrier for the pro-PROTAC FA-S2-MS4048 [205].