We found that decreased DPP4 expression was significantly associated with poor prognosis in overall survival of patients with kidney renal clear cell carcinoma (KIRC; z_score = −5.162245798), LUAD (z_score = −2.004922368), thyroid carcinoma (z_score = −2.837080854), and thymoma (z_score = −2.373081403). This evidence concerns the gene DPP4 and thyroid gland carcinoma.