PTCSC3 and thyroid gland carcinoma: Furthermore, when treating PTCSC3 overexpressed TPC‐1 and BCPAP cells with the proteasome inhibitor MG132, the protein levels of endogenous PGK1 increased more than those in control cells (Figure 4F), suggesting that PTCSC3 promotes the proteasome‐dependent degradation of PGK1 in thyroid cancer cells.