In addition to B-cell depletion, modification of B-cell and T-cell phenotypes as well as cytokine profiles may be involved in the action of rituximab.

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers in the world, and hepatitis B and C viruses are the main causative agents for high incidence of HCC. 1 Although the mechanisms underlying HCC development have been widely investigated from both points of direct and indirect effects of the viruses, 2 they are still open to debate. Whatever the mechanisms involved, these viral infections are correlated with a slow, long-lasting disease that is a definite risk for neoplastic degeneration.Telomeres are composed of tandem arrays of a short DNA sequence, d(TTAGGG)n in vertebrates, and associated proteins. They are essential genetic elements and stabilize the natural ends of linear eukaryotic chromosomes. 3 The endreplication problem, the inability of DNA polymerases to completely replicate the end of a DNA duplex, 4 results in telomere shortening in proportion to cell replication. 5 Because severity of persistent hepatocellular degeneration might indicate a risk for HCC development, an extent of telomere erosion has a possibility to be a predictor for HCC development in the liver under chronic inflammation.The standard and currently most reliable method for evaluating telomere length uses Southern analysis of terminal restriction fragment (TRF) lengths. 6 TRFs, however, contain DNA other than uniform telomeric repeats, 7 and the analysis requires several micrograms of high-molecular-weight genomic DNAs. In addition, telomere length varies among individuals prior to replicative histories. 8 Although this variation should be normalized before comparison of telomere length among patients, all previous reports describing telomere alteration in chronic liver diseases were unfortunately evaluated without any standardization. 9-12 These technical limitations inherent in the complexity of TRF make it difficult to analyze telomere dynamics using clinical materials, especially in the case that only a small specimen is available.In this study, we first evaluated reliability and reproducibility of a slot-blot analysis to detect alteration of telomeric repeats content. Next, we determined the content in various liver tissues. For comparison of the content in the liver with respect to chronic inflammation, we standardized the content

Both loss of heterozygosity (LOH) and replication error (RER) are considered to be phenotypes of genomic instability. To unveil the role of the genomic instability in hepatocarcinogenesis, frequencies of LOH and RER were simultaneously determined in 15 hepatocellular carcinomas (HCCs), surrounding nontumorous liver tissues (SL), and 13 liver tissues with chronic viral hepatitis void of cancer (NC) by referencing peripheral blood leukocytes (PBLs) from the corresponding donor using 18 microsatellite markers spread throughout the genome. LOH was significantly frequent in HCC compared with that in SL or NC (P ‫؍‬ .005, P ‫؍‬ .0003, respectively) and observed preferentially at particular microsatellite loci, D1S204, D2S123, D8S1106, D9S266, D16S748, and D19S601. Although the higher prevalence of RER was also significant in HCC compared with that in NC (P ‫؍‬ .03), in most cases the errors were detected at very low frequencies and random loci. Both LOH and RER tended to appear more prevalently in SL than in NC. The occurrence rate of LOH was higher in the tissues associated with hepatitis B virus (HBV) than with hepatitis C virus (HCV) infection especially in HCC (P ‫؍‬ .03). When referencing SL instead of PBLs, the prevalence of LOH and RER in HCC significantly decreased (P ‫؍‬ .02 and P ‫؍‬ .03, respectively). These results suggest that LOH is closely associated with multistep hepatocarcinogenesis especially under HBV infection, but RER is imperceptibly associated. The quantitative evaluation of the frequency of LOH by referencing PBLs may be a useful predictor for HCC development in chronic liver diseases. (HEPATOLOGY 2000;31:1246-1250.) Hepatocellular carcinoma (HCC) is one of the most common human cancers especially in areas in which hepatitis B virus (HBV) or hepatitis C virus (HCV) infection is prevalent. 1 Although the molecular mechanisms of hepatocarcinogenesis have not been elucidated yet, a long-lasting inflammation induced by the hepatitis virus is a definite risk for neoplastic degeneration and the accumulation of genetic alterations. Thus, it is not difficult to assume that genomic instability, such as loss of heterozygosity (LOH) and replication error (RER), has already appeared in the premalignant status and increased through hepatocarcinogenesis.LOH and RER analyses have been performed in HCC as well as in other types of cancers. [2][3][4][5][6][7][8][9] In relation to RER, its prevalence in HCC was extremely low compared with that in so called RER-positive cancers such as hereditary nonpolyposis colorectal cancer. [7][8][9][10][11] It is possible that the lower incidence of RER was derived from the employment of surrounding noncancerous liver tissues (SL) as a referencing material, in which genetic alterations might have already been accumulated. The same problem might be involved in LOH analyses. Thus, it might be ideal to reevaluate the frequency of LOH and RER in chronic liver diseases using the tissues out of the liver as referencing materials.In this study, we simultaneously investigated LOH a...