Heart transplantation (HTx) is an established and effective treatment for advanced heart failure [1]. The long-term prognosis after HTx has continuously improved as a consequence of reduced early post-transplant mortality [2]. In Japan, the survival rates at 5, 10, and 15 years after HTx are 92.7%, 89.6%, and 81.8%, better than those in Europe and the USA [3]. However, the incidence of de novo malignancy increases in the late period and is one of the major causes of death after HTx [4]. Malignancy negatively impacts the prognosis after HTx, regardless of the type of malignancy [5]. The risk of de novo malignancy in heart transplant recipients was reported to be 2-4 times higher than that in the general population [5-7]. Additionally, heart transplant recipients have a 4 times higher risk compared to renal transplant recipients due to their intensive immunosuppression therapy [5,6]. There are several