Immunocytochemical identification of neoplastic cell clone in phase S of cell cycle in transplantable rat tumors

Wistar and Buffalo rats of both sexes, aged 4 months, were divided into three groups: I which was given an intramuscular injection of 3 x 10(6) cells of Morris hepatoma (Buffalo males), II--subcutaneous injection of 3 x 10(4) cells of mammary gland carcinoma (Wistar females), III--intraperitoneal injection of 3 x 10(4) cells of Yoshid sarcoma (Wistar males). The animals were killed: in group I--19, group II--13 and in group III--6 days after tumor transplantation. Twenty four hours before euthanasia the rats were given 5-brome-2'-deoxyuridine (BRd-U) at a dose of 50 mg/kg body mass. The control group consisted of animals with tumour. They were not treated with BRd-U. Immunocytochemical reaction was performed on the sections of tumors, using monoclonal anti-BRd-U clone BU-33, Sigma. Computer measurements of tumor cells were carried out. There was a high similarity in morphological parameters between two kinds of cancer, and clear differences between them and Yoshid sarcoma. The main difference was noted in a twofold increase in the quantity of synthesised DNA in the nuclei of sarcoma cells. Immunocytochemical identification of tumor cells in phase S of the cell cycle with the use of monoclonal anti-BRd-U antibody is a precise and quick method of estimation of their proliferative potential.