Expression of c-Myc, c-Fos, and c-jun in hepatocellular carcinoma.
BACKGROUND
Increased expression of the proto-oncogene c-myc is a common phenomenon in hepatocellular carcinoma (HCC). The proto-oncogenes c-fos and c-jun are involved in cell cycle progression and cellular proliferation.


METHODS
The objective of this study was to elucidate the mechanism of hepatocarcinogenesis with regard to the expressions of c-myc, c-fos, and c-jun. One hundred fifty biopsied HCC specimens were stained immunohistochemically for the above phenotypic markers both in tumor tissue and in adjacent nontumor tissue.


RESULTS
Although the expression of c-myc was high (74%) in tumor tissue, it was significantly less compared with the expression in nontumor tissue (100%; P = 0.0002). The expression of c-myc was inversely proportional to the grade of differentiation in tumor tissue (P = 0.0108; correlation coefficient [r] = -0.244); that is, tissue with poorer histologic differentiation had a lower level of c-myc expression. There were inverse associations between the expression of c-myc and the expression of mutated p53 (P = 0.0017; r = -0.285) as well as the expression of Ki67 (P = 0.057; r = -0.147). There was significantly high expression of c-fos in tumor tissue compared with the expression in nontumor tissue (91% vs. 0%; P < 0.0001). Both the tumor tissue and the nontumor tissue had high levels of expression of c-jun (96.53% and 100%, respectively). There was a trend toward a positive association between the expression of c-fos and the expression of c-jun in tumor tissue (P = 0.07; r = 0.162).


CONCLUSIONS
Because c-myc is a known inducer of wild type p53, decreased c-myc expression may lead to uncontrolled cell growth because of the lack of p53 expression that normally induces apoptosis. The coordinated expression of c-fos and c-jun in HCC may reflect the coordinated tumor cell cycle of progression and proliferation; however, future studies are required to elucidate this possibility.
Yuen
M F
MF
Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, People's Republic of China.
Wu
P C
PC
Lai
V C
VC
Lau
J Y
JY
Lai
C L
CL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D001706:Biopsy; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000503:physiopathology; D002453:Cell Cycle; D002471:Cell Transformation, Neoplastic; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D016762:Genes, fos / Q000235:genetics*; D016758:Genes, jun / Q000235:genetics*; D016259:Genes, myc / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D000090063:Proto-Oncogene Mas