(4S) -PROTAC SOS1 degrader-1 (diTFA) is a potent PROTAC SOS1 degrader. (4S) -PROTAC SOS1 degrader-1 (diTFA) decreases the expression of pERK and RAS-GTP level in a dose-dependent manner. (4S) -PROTAC SOS1 degrader-1 (diTFA) significantly inhibits the tumor growth in vivo[1].