<i>Background and Objectives</i>: This study aimed to evaluate associations between dental caries, periodontal pockets, and radiologically detected periapical lesions in relation to serum levels of Dickkopf-1 (Dkk-1) and tartrate-resistant acid phosphatase 5B (TRAP-5B) in oncologic patients with ear, nose, and throat (ENT) cancer compared with healthy controls. The gene discussed is ACP5; the disease is dental caries.