[Malignancy in gastric cancer, with special reference to the distribution of BrdU-labelled cells]

Analysis of the distribution of BrdU-labelled cells was performed on 50 gastric cancers and the results correlated with histologic findings and DNA ploidy patterns. Patients were administered a intravenous infusion of 1g BrdU 1 hour before laparotomy. The resected specimen was fixed in 70% ethanol, embedded in paraffin, and cut into thin sections. The sections were stained by ABC method. The BrdU labelling index (LI) was calculated by counting 1000 tumor cells in superficial, internal and deep layers, respectively. DNA ploidy was analyzed using flow cytometry. The mean of BrdU LI of superficial layer was 19.6%, which was significantly higher than that of internal layer and deep layer. The distribution patterns were classified into three types (labelling types) as follows: Superficial type, BrdU LI of superficial or internal layer was higher than that of deep layer; deep type, BrdU LI of deep layer was higher than that of superficial or internal layer; diffuse type, BrdU LI of each layer was equal. Thirty of 50 cases were superficial type. But in diffuse type (13 cases), incidence of lymph node metastasis, vessel invasion, larger than 4 cm in tumor size, differentiated type and aneuploid were significantly higher than those in superficial type.