Cell kinetic study of human carcinomas using bromodeoxyuridine and immunohistochemistry

: Cell kinetics of human carcinomas was studied in vivo using immunohistochemical technique with bromodeoxyuridine (BrdU). Relationship between tumor growth and DNA synthesis was analysed in 7 human tumor xenografts serially transplanted into nude mice by in vivo administration of BrdU. The specimens were processed in immunohistochemical staining of ABC method using anti-BrdU monoclonal Ab. The labeling index (LI) was determined as the ratio of stained cells to tumor cells. It was found that LI tended to increase transiently at the initial stage of exponential growth phase and remained stable thereafter. Correlation between tumor doubling time and LI was observed with statistical significance. In 29 cancer patients including 24 gastric and 5 colorectal cancers, LI was also determined in vivo. In advanced gastric cancers, LIs were higher at the site of invasion than the central area. LIs of gastric cancers in stage I were lower than those in stage II, III and IV. Considering the data of human tumor xenografts, it was suggested that the stage II, III and IV gastric cancers might be biologically different types of cancers compared to stage I gastric cancers.