Characterization of liver-cirrhosis nodules by analysis of gene-expression profiles and patterns of allelic loss

Abstract

To disclose genetic mechanisms involved in development or progression of hepatocellular carcinoma (HCC), we used a genome-wide cDNA microarray consisting of 8,448 genes to compare gene-expression profiles among 12 liver-cirrhosis nodules (LCNs) and five specimens of HCC excised from a single patient and carefully prepared by laser-capture microdissection (LCM). The expression patterns enabled us to identify 72 genes that were frequently upregulated and 57 that were downregulated specifically in the LCN specimens as compared to the HCCs. We also documented upregulation of 31 genes and downregulation of seven others in both HCC and LCN tissues. Several types of intracellular kinase, including receptor-type kinase, were upregulated in LCNs. Expression patterns of HCCs and LCNs generally represented two genetically distinct groups when subjected to a hierarchical clustering analysis, although expression profiles of two of the LCNs resembled the HCC pattern. Analysis of allelic losses at microsatellite loci revealed that LCNs showed frequent loss of heterozygosity (LOH) (33%) in chromosomal regions 6q and 22q; over half of the LCNs had lost an allele for at least one of the 28 loci examined. The presence of early genetic changes among LCNs, with additional genetic changes occurring during formation of HCCs, suggests that hepatocellular carcinogenesis follows the multistep model established for colon cancers and that some LCNs may be precancerous lesions.

IP-10, p53, and Foxp3 Expression in Hepatocytes of Chronic Hepatitis B Patients with Cirrhosis and Hepatocellular Carcinoma

“…To understand gene dysregulation in liver diseases, the cDNA microarray technology has been used for global gene expression analysis of hepatitis viruses, 13 chronic viral hepatitis, 14 cirrhotic nodule, 15 dysplastic nodules, 16 and HCC. 17 Although a few studies have investigated dysregulated genes in cirrhotic nodules, very little is known about the genes implicated in the pathophysiologic change of LC, or their relationship with the degree of decompensation.…”

Microdissecção e captura a laser na investigação do gene TP53 em tecidos incluídos em parafina

“…Ao fi nal, o cap é retirado do sistema com um suporte próprio e acoplado a um tubo Ependorff contendo solução para extração do DNA. (14) . O material foi mantido a -20 o C até o momento da extração do DNA.…”

“…Nesse estudo, o DNA não foi extraído de lesões histológicas específi cas, de modo que a análise molecular consistiu em um pool de células procedentes tanto de lesões neoplásicas e pré-neoplásicas como dos tecidos normais adjacentes a elas. Assim, não se pode afastar a possibilidade de que a ausência de alterações moleculares tenha resultado de "diluição" do DNA alterado, já que as células neoplásicas e pré-neoplásicas constituem uma população relativamente pequena do tecido analisado, criando condições para resultados falso negativos (14) . Para evitar essa fonte de erro, as alterações do genoma devem ser preferencialmente pesquisadas em amostras de células transformadas, procedentes de lesões pré-neoplásicas ou neoplásicas específi cas.…”