Nodules of less-differentiated tumor within or adjacent to hepatocellular carcinoma: relative expression of transforming growth factor-alpha and its receptor in the different areas of tumor.

Expression of transforming growth factor-alpha (TGF-alpha) and its receptor, the epidermal growth factor receptor (EGFR), in hepatocellular carcinomas (HCCs) and adjacent nontumorous livers from 25 Japanese patients were examined using immunoperoxidase staining of paraffin-embedded sections. TGF-alpha was detected in 24 of 25 (96%) HCCs and 23 of 24 (96%) available adjacent nontumorous livers. EGFR was detected in 16 of 25 (64%) HCCs and 17 of 24 (71%) adjacent nontumorous livers. TGF-alpha and EGFR were not detected by immunohistochemical staining in normal livers. Fifteen of 25 HCCs contained an apparent area of a second tumor (two of the 15 also contained a third tumor) that had a less-differentiated histological grade developing within or adjacent to the first tumor. In those cases, staining in the less-differentiated area of tumor was usually less intense than in the more highly differentiated area (80% of cases for TGF-alpha; 91% for EGFR). These data confirm that increased expression of TGF-alpha and EGFR occur frequently in human HCC. Furthermore, the detection of greater staining in more highly differentiated portions of the tumors suggests that increased expression of TGF-alpha and EGFR may be events of the early stages of human hepatocarcinogenesis.