In in vitro tumor cell models (human prostate (LNCaP), breast (MDA-MB-231), lung (H1703) carcinoma, and chordoma (JHC7) cells), expression of HLA-ABC, CEA, MUC-1, and ICAM-1 was increased after proton (8 Gy) and γ-irradiation (8 Gy), as well as sensitivity of the tumor cells to CEA-specific CTL-mediated lysis increased (66). Here, CEACAM5 is linked to chordoma.