[Analysis of proliferative activity in gastric biopsy specimens by combined BrdU and DNA polymerase alpha immunohistochemistry]

To evaluate correctly the proliferative activity of tumor cells, it is necessary to clarify not only S-phase fraction but also the growth fraction of tumor tissues. We used combined BrdU and DNA polymerase alpha (pol-alpha) immunohistochemistry to gastric biopsy specimens, and analyzed the proliferation of the neoplastic lesions of various degrees of malignancy. The results were as follows: The distribution of pol-alpha positive cells were almost the same as that of BrdU positive cells, but the percentage of pol-alpha positive cells was higher than that of BrdU positive cells irrespective of the mucosal specimens. In the adenomas, both BrdU and pol-alpha positive cells distributed generally superficially in the mucosal layer. In the well differentiated adenocarcinomas, both BrdU and pol-alpha positive cells distributed diffusely in the deeper layer of the mucosa. The ratio of the number of BrdU positive cells to that of pol-alpha positive cells, which means the S-phase fraction in the growth fraction, was higher in the tumor and that higher in the well differentiated adenocarcinomas than that of the adenomas. In conclusion, the combined BrdU and pol-alpha immunohistochemistry in gastric biopsy specimens are useful to evaluate the degree of malignancy.