OBJECTIVES - To explore the significance of PTEN (phosphatase and tensin homolog deleted on chromosome 10) in the development of human primary hepatocellular carcinoma (HCC).
METHODS - PTEN protein expression in cancerous liver tissues and paired para-carcinoma liver tissues from 60 HCC patients was detected by immunohistochemistry and PTEN mRNA expression was analyzed by northern blot. The significance of PTEN in the development of HCC was analyzed by investigating the relationship between the expression levels of PTEN protein and mRNA, and the clinicopathological parameters of HCC patients.
RESULTS - PTEN protein was immunohistochemically stained in the cytoplasmic region of para-carcinoma liver tissues in all the 60 patients, while only 48.3% (29/60) of the patients were positive for PTEN protein in cancerous liver tissues. The positive rate of PTEN protein in HCC tissues were relative to the histological gading and the presence of tumor thrombus. In grade I - II, III, and IV, the positive rates were 84.0%, 23.8%, and 21.4% respectively, and in the group with tumor thrombus was 26.7%, while in the group without tumor thrombus was 55.6%. Northern blot showed that there existed four PTEN mRNA transcripts with the length of 5.5kb, 4.4kb, 2.4kb, and 1.8kb respectively. The level of PTEN mRNA expression in HCC tissues was much lower than that in the paired para-carcinoma liver tissues. The low expression level of the 5.5kb and 4.4kb transcripts was significantly associated with serum AFP value, presence of tumor thrombus, state of satellite lesion and histological grading. The low expression level of the 2.4kb transcript in HCC was significantly associated with the presence of tumor thrombus and satellite lesions in HCC patients. However, no evident relationship between the lowered expression level of the 1.8kb transcript and the clinicopathological parameters of HCC was observed in these 60 patients.
CONCLUSIONS - Down-regulation of PTEN expression may play an important role in the development of HCC and the expression level of PTEN may be a potential adjuvant parameter in forecasting the progress and prognosis of HCC.