Overexpression of tetraspanin CO-029 in hepatocellular carcinoma

Background/Aims: The molecules involved in the progression of hepatocellula r carcinoma (HCC) are not fully understood. The aim of this study was to el ucidate the crucial genes involved in cancer progression and metastasis. Methods: Selectively expressed genes were screened using differential displ ay analysis, and then further analyzed by real-time quantitative reverse-tr anscription polymerase chain reaction (RT-PCR) and immunohistochemistry. Results: Tetraspanin CO-029 was found to be frequently and significantly ov erexpressed in HCC. Real-time quantitative RT-PCR showed that the CO-029 mR NA level was 1.7 times higher (P = 0.030) in cancerous tissues than in nonc ancerous tissues. mRNA expression of the other tetraspanins, CD9 and CD82, was downregulated in HCC, especially in tumors with intrahepatic spreading (portal vein invasion and/or intrahepatic metastasis). In contrast, mRNA ex pression of CO-029 tended to be increased in cancerous tissue showing intra hepatic spreading compared with tumors without such spreading. Immunohistoc hemical analysis revealed that CO-029 was overexpressed in poorly different iated HCCs compared with well to moderately differentiated tumors (P < 0.00 1), and in HCCs showing intrahepatic spreading compared with those without spreading (P = 0.019). Conclusions: Our findings suggest that CO-029 has some roles in the promoti on of metastasis of HCC. (C) 2001 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.