TPO and hypothyroidism: Although Toi et al. [18, 19] and Maekura et al. [20] reported that thyroid peroxidase (TPO) antibody and thyroglobulin antibody (TgAb) levels before ICI therapy were predictive factors for the development of hypothyroidism, whereas our study showed no association with TPO antibody levels but suggested an association with TgAb levels (P = 0.05).