It has been known that transglutaminase C (TGase C, TGase II) is directly participated in the DNA organization of chromosome, and affects the cellular processes such as proliferation, differentiation, and apoptosis of cells, but still not known what mechanism is working on. In this study, the cytogenetic and the immunohistochemical methods were used to observe the TGase C expression in the nuclear chromosome of the proliferating cells, especially in mitotic stage. The human gastric adenocarcinoma (SNU-1) cell line was used for immunohistochemistry and antisense inhibition study in vitro. The present study was also aimed to disclose the efficiency of antisense inhibition by using antisense oligonucleotide DNA labeled with fluorescence, and found that anti-TGase C probe was diffusely infiltrated into the cytoplasm and the nucleus of the cell. By the antisense inhibition the nuclei of SNU-1 cells became rough nuclear shape, as they were greatly reduced in TGase C immunoreactivity both for the normal and apoptotic SNU-1 cells. However, it is clearly presumed that the TGase C directly interacts with the chromosome of SNU-1 cells and it may play an important role in the division and organization of the chromosome during the mitotic stage.