[Expression of mitogen-activated protein kinase and its upstream regulated signal in human hepatocellular carcinoma].

Objective: To detect protein expression of ERK(1), ERK(2), JNK(1), p38 and MEK(1), MEK(2) in human hepatocellular carcinoma and adjacent non-neoplastic liver.
Methods: In 16 surgically resected hepatocellular carcinoma and para-carcinoma tissues, Western blotting was used to detect expression of ERK(1), ERK(2), JNK(1), p38 and MEK(1), MEK(2).
Results: In all cases, ERK(1), ERK(2), p38 expression in hepatocellular carcinoma was significantly higher than that in para-carcinoma: integral optic density (IOD) of ERK(1) was 300 +/- 98 in carcinoma and 98 +/- 48 in para-carcinoma tissues (t = 2.519, P < 0.01); IOD of ERK(2) was 587 +/- 83 in carcinoma and 232 +/- 96 in para-carcinoma tissues (t = 2.745, P < 0.01); IOD of p38 was 270 +/- 85 in carcinoma and 107 +/- 88 in para-carcinoma tissues (t = 2.491, P < 0.01). JNK(1) expression in hepatocellular carcinoma was significantly lower than that in para-carcinoma; IOD of JNK(1) was 111 +/- 93 in carcinoma and 292 +/- 109 in para-carcinoma tissues (t = 2.473, P < 0.01). Protein levels of MEK(1) and MEK(2) in carcinoma were significantly higher than in para-carcinoma. IOD of MEK(1) was 1 418 +/- 244 in carcinoma and 806 +/- 90 in para-carcinoma tissues (t = 2.546, P < 0.01). IOD of MEK(2) was 1 041 +/- 122 in carcinoma and 468 +/- 40 in para-carcinoma tissues (t = 2.861, P < 0.01).
Conclusions: ERK(1), ERK(2), MEK(1) and MEK(2) in the signal transduction pathway for cell proliferation are significantly overexpressed and the expression of JNK(1) is lower in hepatocellular carcinoma. Their unbalance is one of the important reasons for the over growth and infinite proliferation of the hepatocellular carcinoma cell. The p38 and JNK(1) may be activated by different pathway.