BACKGROUNDChromosomal instability (CI) leading to aneuploidy is one form of genetic instability, a characteristic feature of various types of cancers. Recent work has suggested that CI can be induced by a spindle assembly checkpoint defect. The aim of the current study was to determine the frequency of a defect of the checkpoint in hepatocellular carcinoma (HCC) and to establish whether alterations of genes encoding the checkpoint were associated with CI in HCC.METHODSAneuploidy and the function of the spindle assembly checkpoint were examined using DNA flow cytometry and morphologic analysis with microtubule disrupting drugs. To explore the molecular basis, the authors examined the expression and alterations of the mitotic checkpoint gene, BUB1, using Northern hybridization and direct sequencing in 8 HCC cell lines and 50 HCC specimens. Furthermore, the authors examined the alterations of other mitotic checkpoint genes, BUBR1, BUB3, MAD2B, and CDC20, using direct sequencing in HCC cell lines with aneuploidy.RESULTSAn impaired spindle assembly checkpoint was found in five (62.5%) of the eight aneuploid cell lines. Transcriptional expressions of the BUB1 gene appeared in all cell lines. While some polymorphic base changes were noted in BUB1, BUBR1, and CDC20, no mutations responsible for impairment of the mitotic checkpoint were found in either the HCC cell lines or HCC specimens, which suggests that these genes did not seem to be involved in tumor development in HCC.CONCLUSIONSThe loss of spindle assembly checkpoint occurred with a high frequency in HCC with CI. However, other mechanisms might also contribute to CI in HCC. Cancer 2002;94:2047–54. © 2002 American Cancer Society.DOI 10.1002/cncr.10448

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BACKGROUND Microsatellite instability occurs frequently in hereditary nonpolyposis colorectal carcinoma, in sporadic gastrointestinal carcinoma, and in other tumors. In these tumors, slippage‐related frameshift mutations have been detected at coding mononucleotide repeats in genes such as those for transforming growth factor‐β receptor type II (TGFβRII), mannose 6‐phosphate/insulinlike growth factor II receptor (M6P/IGFIIR), hMSH3, hMSH6, and Bcl‐2–associated X protein (BAX). Because these genes regulate cell growth or repair DNA mismatches, loss of their function is thought to promote tumor development. The authors screened for these frameshift mutations and investigated the incidence of microsatellite instability (MI) in hepatocellular carcinoma (HCC) in Japan. METHODS Fifty HCC samples were analyzed in this study. The authors used polymerase chain reactions to screen for frameshift mutation at the TGFβRII (A)10 tract, the M6P/IGFIIR (G)8 tract, the hMSH3 (A)8 tract, the hMSH6 (C)8 tract, and the BAX (G)8 tract. For MI analysis, matched tumor and nontumor liver DNA were investigated with respect to 10 microsatellite loci. RESULTS No frameshift mutation was detected in any case, and only 4% of these cancers exhibited MI in comparisons between tumor and nontumor liver specimens. CONCLUSIONS This study suggests that frameshift mutation at coding mononucleotide repeats within TGFβRII, M6P/IGFIIR, hMSH3, hMSH6, and BAX genes did not seem to be involved in hepatocarcinogenesis in the Japanese population studied. Cancer 2000;88:1025–9. © 2000 American Cancer Society.

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Hepatocyte growth factor, HB-EGF, bFGF, EGF and TGF-alpha increased DNA synthesis of FLEC. HGF, HB-EGF, bFGF and EGF led to an increase in liver-specific gene expressions; and their effects on differentiation differ as a function of gestation age.

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