KM-HN-1 is a novel cancer/testis antigen recognized by both cellular and humoral immune responses in humans. Immunofluorescent staining of KM-HN-1 (green) was investigated in an esophageal cancer cell line, TE13. In interphase (top panel), KM-HM-1 staining was detected throughout the nucleus (red), especially bright at the nuclear boundary with weak staining in the cytoplasm. During mitosis (lower panels), KM-HN-1 co-localized (yellow) with chromosomes stained by propidium iodide (red). For further details, please see Monji et al. on page 6047 in this issue.