TSC1 and neoplasm: Because Tsc1 − / − or Tsc2 − / − MEFs have low tumorigenic ability in vivo [39], we constructed a novel cell line (NTC/T1 null cells) with potent tumorigenicity derived from a subcutaneous tumor formed by the injection of Tsc1 − / − MEFs into nude mice to investigate the in vivo role of ERO1α (Supplementary Fig. 3A–E).