Proliferating cell nuclear antigen and grade of malignancy in small hepatocellular carcinoma--evaluation in US-guided specimens.

Background/Aims: We investigated the value of the proliferating cell nuclear antigen labeling index ratio (PCNA-LI ratio: PCNA-LI of cancer / PCNA-LI of surrounding non-cancerous liver tissue) to clarify the prognosis of the patients bearing small hepatocellular carcinomas (HCC) less than 20 mm in diameter and treated by percutaneous ethanol injection therapy (PEIT). Material and Methods: Twenty eight HCC patients who had received PEIT were divided into 3 groups. The non-recurrence (NR) group in which no new lesions were observed for at least 18 months after PEIT (13 patients), the early recurrence group (ER) in which lesions recurred within one year (6 patients), and the late recurrence group (LR) in which lesions recurred more than one year after PEIT (9 patients). Immunohistochemical staining of PCNA was done using biopsied specimens. Results: The PCNA-LI ratio in 37 well differentiated, 13 moderately differentiated, 11 poorly differentiated HCC were 1.86±0.55, 3.33±o.51, and 4.75±0.81 (mean±SD), respectively. The ratio in ER group (4.57±0.57) was significantly higher than that in LR (2.04±0.61) and NR group (1.87±0.62) and the PCNA-LI ratio tended to correlate with the periods until the development of recurrent lesions in cases of ER group. Conclusions: These results indicate the PCNA-LI ratio, in conjunction with the histological grade, is a useful marker for evaluating the grade of malignancy, and for predicting the period until recurrence after treatment of small HCC.