CELLULAR-DISTRIBUTION OF 92-KD TYPE-IV COLLAGENASE GELATINASE-B IN HUMAN HEPATOCELLULAR-CARCINOMA

To examine the possible involvement of gelatinase B in human hepatocel lular carcinoma (HCC), cellular localization of transcripts and protei n of gelatinase B were studied by using in situ hybridization and immu nohistochemistry. Transcripts for gelatinase B were observed in tumor cells in 22 cases of 27 HCCs and also in dysplastic nodules. However, there was no significant difference in the expression among histologic al grades of HCC. The expression was mostly homogeneous, but the inten sity varied with the nodules. Of 13 cases with capsular invasion, 12 e xpressed gelatinase B, whereas 10 of 14 without capsular invasion did (P < 0.05). Gelatinase B transcripts were commonly observed in the sin usoidal cells of the hepatic lobules, in mesenchymal cells both in fib rous capsules and around the necrosis, and also in some undefined cell s of the portal tracts of noncancerous liver. Localization of gelatina se B protein was mostly similar to but sometimes different from that o f the transcripts in cancer nodules. In conclusion, the expression of gelatinase B appears to be an important characteristic of malignant tr ansformation of hepatocytes. The findings suggest that gelatinase B sy nthesized by cancer cells plays an important role in the growth and in vasion of HCC by degrading surrounding extracellular matrices.