PCSK1 and medullary thyroid gland carcinoma: Among the top 15 hub genes, the 11 highest ranked ones, including CHGA, PTPRN, PCSK1, CHGB, SNAP91, RAB3A, SV2A, KIF5C, CDK5R2, SCG2 and APLP1 composed module 1 (Figure 4C), indicating their functional connection in MTC.