Signal transducer and activator of transcription (STAT)-3 (encoded by STAT3) induces initiation, progression, proliferation, metastasis, angiogenesis, EMT, self-renewal stemness, migration, invasion, immune escape, and resistance to anoikis, chemotherapy, and radiotherapy of PC cells, and its activation is associated with poor prognosis of patients with PC [115–121]. The gene discussed is STAT3; the disease is pachyonychia congenita.