High resolution chromosome 3p, 8p, 9q and 22q allelotyping analysis in the pathogenesis of gallbladder carcinoma

Abstract

Our recent genome-wide allelotyping analysis of gallbladder carcinoma identified 3p, 8p, 9q and 22q as chromosomal regions with frequent loss of heterozygosity. The present study was undertaken to more precisely identify the presence and location of regions of frequent allele loss involving those chromosomes in gallbladder carcinoma. Microdissected tissue from 24 gallbladder carcinoma were analysed for PCR-based loss of heterozygosity using 81 microsatellite markers spanning chromosome 3p (n=26), 8p (n=14), 9q (n=29) and 22q (n=12) regions. We also studied the role of those allele losses in gallbladder carcinoma pathogenesis by examining 45 microdissected normal and dysplastic gallbladder epithelia accompanying gallbladder carcinoma, using 17 microsatellite markers. Overall frequencies of loss of heterozygosity at 3p (100%), 8p (100%), 9q (88%), and 22q (92%) sites were very high in gallbladder carcinoma, and we identified 13 distinct regions undergoing frequent loss of heterozygosity in tumours. Allele losses were frequently detected in normal and dysplastic gallbladder epithelia. There was a progressive increase of the overall loss of heterozygosity frequency with increasing severity of histopathological changes. Allele losses were not random and followed a sequence. This study refines several distinct chromosome 3p, 8p, 9q and 22q regions undergoing frequent allele loss in gallbladder carcinoma that will aid in the positional identification of tumour suppressor genes involved in gallbladder carcinoma pathogenesis. British Journal of Cancer (2002) Gallbladder carcinoma (GBC) is a relatively uncommon neoplasm which demonstrates considerable geographic and gender variation in incidence (Albores-Saavedra and Henson, 2000). For unknown reasons, it is one of the most frequent neoplasms in Chile, where it is the leading cause of cancer deaths in females (Lazcano-Ponce et al, 2001). It has been well established that invasive GBC is preceded by preneoplastic lesions, including dysplastic changes of the gallbladder epithelium (Albores-Saavedra and Henson, 2000). There is a very limited information about the molecular changes involved in the pathogenesis of GBC (Wistuba and Albores-Saavedra, 1999).It is now well recognised that tumourigenesis is a multistep process resulting from the accumulation of sequential genetic alterations (Fearon and Vogelstein, 1990). In addition to oncogene activation, inactivation of tumour suppressor genes (TSGs) has been shown to play an important role in tumourigenesis (Fearon and Vogelstein, 1990). Allelic loss, manifested as loss of heterozygosity (LOH) at polymorphic loci, is recognised as a hallmark of tumour suppressor genes, whose other allele is inactivated by point mutations or by some other mechanism (Knudson, 1985). Thus, the finding of chromosomal regions with frequent incidence of LOH in a neoplasm suggests that those regions may harbour one or more TSGs.Our recent genome-wide allelotyping analysis on GBC indicated that allelic losses at multiple sites of the genome are freque...

Mitochondrial DNA Mutation at the D310 (Displacement Loop) Mononucleotide Sequence in the Pathogenesis of Gallbladder Carcinoma

“…Our finding of relatively frequent (24%) mutation at the D310 sequence in chronic cholecystitis without cancer supports the hypothesis that a subset of gallbladders with chronic inflammation may be at greater risk of progression to cancer. Of interest, in our previous studies similar frequencies of allele loss and genetic instability (24), gene aberrant methylation (35), and TP53 gene abnormalities 5 have been detected in chronic cholecystitis specimens. All of the epidemiological studies have shown that gallstones are the primary risk factor for GBC (reviewed in Ref.…”

“…Because only a small fraction of patients with cholelithiasis and chronic cholecystitis develop gallbladder cancer (1) it is important to identify the factors that induce malignant progression. The development of epithelial cancer, including GBC (4,24,(33)(34)(35), requires multiple mutations. It is possible that those preneoplastic lesions that have accumulated multiple mutations are at higher risk for progression to invasive cancer.…”

Aberrant Promoter Hypermethylation of Multiple Genes in Gallbladder Carcinoma and Chronic Cholecystitis

“…Most studies have focused on mutations of dominant oncogenes (K-ras) or tumor suppressor genes (TSGs) [TP53, P16 INK4A , and FHIT (3)(4)(5)]. Genomewide and specific chromosome arm allelotyping analyses indicated that allelic losses at multiple sites of the genome are frequent in this neoplasm, suggesting the involvement of multiple TSGs in its pathogenesis (6,7). Recently, Hansel et al (8), using a RNA-based global gene expression microarray analysis of ϳ22,000 transcripts in a series of biliary tract tumors including 10 GBC specimens, detected a number of abnormally expressed genes, most of which had not been described previously in these tumor types.…”

Hrk Mediates 2-Methoxyestradiol–Induced Mitochondrial Apoptotic Signaling in Prostate Cancer Cells

“…Hrk inactivation is also inversely correlated with apoptosis indices in tumors (17)(18)(19). Hrk is located in chromosome 12q13 (20) where loss of heterozygosity is often observed in several types of human tumors (21)(22)(23). Moreover, Hrk overexpression suppresses cell growth in prostate, breast, and ovarian cancer cells (24).…”