Previous studies have reported that the inhibitors corresponding to several RTKs, such as EGFR (Dai et al., 2021), ERBB2 (Raja et al., 2011; Chen et al., 2020) and FGFR, can generate synergistic effects on cancer cell growth in combination with celastrol, supporting the idea that the reactivation of AKT/ERK signals by celastrol may be caused by RTK feedback. Here, EGFR is linked to cancer.