[A study of relationship between proliferative activity and expressed transferrin receptor content in cancer cells]

Transferrin receptor (TfR) is expressed in the proliferating cells. The author performed an immunohistochemical investigation with TfR and an analysis of TfR protein and mRNA in several cell-lines and examined the relationship between the TfR content and the proliferative activity of the tumor cells. Immunohistochemical examination revealed a strong reaction of the TfR was found in the cell membrane of the epithelial malignant tumors and the non-epithelial malignant tumors showed diffuse staining in the cytoplasm. TfR was almost regulated by the cellular density in the culture dishes. A confluent phase growth led to a low level of TfR. And among the several cell-lines, a higher level of TfR was seen in the cell of the short-doubling time than that of the long-doubling time. In vivo, similarly the rapid growth tumor indicated a high level of TfR rather than the slow growth one. Thus, the level of TfR indicates the degree of the proliferative activity of the tumor cells, so the examination of TfR content is helpful for the determination of the degree of malignancy in each tumor case.