DNA fragmentation and cell proliferation correlated with tumor grade in patients with hepatocellular carcinoma.

Background: DNA fragmentation and cell proliferation in patients with hepatocellular carcinoma (HCC) have not been well described on fine-needle aspiration biopsies (FNABs). To investigate the contribution of apoptosis, a major mechanism of cell death, to the growth of HCC, the authors analyzed both apoptosis and cell proliferation in patients with HCC.

Methods: The authors studied 50 tumors from 50 patients with HCC: Ten tumors were well-differentiated HCC, 24 tumors were moderately differentiated HCC, and 16 tumors were poorly differentiated HCC. The detection of DNA fragments in situ using the terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick-end labeling (TUNEL) assay was applied to investigate active cell death (apoptosis), and the MIB-1 antigen was used to investigate cell proliferation.

Results: The TUNEL indices were 0.34 +/- 0.08, 082 +/- 0.30, and 2.0 +/- 0.95 in well-differentiated HCC, moderately differentiated HCC, and poorly differentiated HCC, respectively. The MIB-1 antigen labeling indices were 6.7 +/- 0.10, 13.2 +/- 3.4; and 26.9 +/- 6.5, respectively, in the same order of tumor differentiation. The differences in both TUNEL and MIB-1 labeling indices were significant between well differentiated HCC, moderately differentiated HCC, and poorly differentiated HCC, and a positive correlation was found between the TUNEL indices and the MIB-1 indices.

Conclusions: Apoptosis (cell death) and cell proliferation increase as the grade of differentiation decreases in HCC, suggesting a rapid turnover of tumor cells in tumors with lower grades of differentiation, and apoptosis may play an important role in the growth of tumors in patients with HCC.