[Expression of signal-regulatory protein alpha (SIRP alpha) in hepatocellular carcinoma].
OBJECTIVE
To investigate the association between signal-regulatory protein alpha (SIRP alpha) and hepatocellular carcinoma (HCC).


METHODS
Thirty-six pairs of HCC and the surrounding noncancerous hepatic tissues, one normal liver cell line and 4 HCC cell lines were used to extract the total RNA and then to prepare the mRNA. The expression of SIRP alpha was determined by Northern blot analysis. The results were analyzed in association with the pathologic characteristics of each sample.


RESULTS
SIRP alpha expressed at low level in 20 of 36 HCC samples and 2 of 4 HCC cell lines. Of the two major hybridization signals, a 3.9 kb transcript in HCC samples was 2-4 times lower than that in the surrounding noncancerous hepatic tissues, whereas a 2.5 kb transcript was 4-6 times as low. Furthermore, a hybridization signal slightly longer than 3.9 kb, being absent in the surrounding noncancerous hepatic tissue, appeared in 9 of the 20 HCC samples. Low level expression of SIRP alpha was observed in all of the 5 HCC samples that had intrahepatic or portal metastasis.


CONCLUSIONS
The expression of SIRP alpha, especially 2.5 kb transcript, was down-regulated in HCC, and an unknown mumber or a variant of SIRP family existed in some tumor tissues. SIRP alpha protein may play an important role in hepatic oncogenesis and metastasis of HCC.
International Co-operative Laboratory for Signal Transduction, Second Military Medical University, Shanghai.
B
B
Li
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H
Wang
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Z
Chen
D000943:Antigens, Differentiation; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D009361:Neoplasm Invasiveness; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D011169:Portal Vein / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D011971:Receptors, Immunologic; D015398:Signal Transduction; D014407:Tumor Cells, Cultured / Q000378:metabolism
D000943:Antigens, Differentiation; D008562:Membrane Glycoproteins; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules; D012333:RNA, Messenger; D011971:Receptors, Immunologic