Loss of heterozygosity analysis of microsatellites on multiple chromosome regions in dysplasia and squamous cell carcinoma of esophagus / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the molecular alterations related to the carcinogenesis of esophageal squamous cell carcinoma (SCC), and also to find some molecular markers for the early detection of this cancer.</p><p><b>METHODS</b>The resected tumor specimens and dysplasia tissues from 34 patients with esophageal cancer as well as their matched blood DNAs were analyzed for loss of heterozygosity (LOH) at 16 microsatellites by using PCR and fluorescence-based DNA sequencing technology. Mild and moderate dysplasia was classified as light-grade dysplasia (LGD), and severe dysplasia as high-grade dysplasia (HGD). The frequencies of LOH at 16 microsatellites were compared between tissue specimens with different histological diagnosis.</p><p><b>RESULTS</b>The total frequency of LOH for 16 microsatellites increased significantly in more severe lesions. There was significant difference in the frequency of LOH among LGD and HGD as well as SCC. A total of eight loci (D3S1597, D3S2452, D3S1285, D4S174, D5S2501, D9S125, D13S153 and D17S786) presented LOH in LGD samples. A reversion from LOH to retain of heterozygosity was observed at loci D3S2452, D4S174, D9S125 and D17S261 respectively when compared HGD with SCC samples obtained from 4 patients.</p><p><b>CONCLUSIONS</b>An accumulation of molecular alterations would be needed during the carcinogenesis of esophageal cancer. LOH analysis at some specific loci would be helpful for the early detection of esophageal cancer. The genetic heterogeneity possibly exists in the tumorigenesis of esophageal cancer.</p>

Study on human papillomavirus infection and loss of heterozygosity of microsatellite in esophageal cancer / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the loss of heterozygosity(LOH) at 14 microsatellites in esophageal cancer and human papillomavirus (HPV) infection.</p><p><b>METHODS</b>HPV-16,18 DNA was examined in 112 tumor specimens using fluorescence quantitative PCR. 112 tumor specimens and their matched blood DNAs were analyzed for LOH at 14 microsatellites by PCR and fluorescence-based DNA sequencing technology. The frequencies of LOH at 14 microsatellites were compared between HPV positive and negative specimens.</p><p><b>RESULTS</b>High frequency of LOH was observed among chromosome arms 3p, 9p, 13q, 17p and 17q. The frequency of LOH was significantly higher at loci D13S260 and D6S497 in HPV positive specimens, comparing with HPV negative ones.</p><p><b>CONCLUSION</b>The findings regarding loci with allele loss indicated that widespread chromosome instability might have existed in esophageal cancer. HPV positive specimens with higher frequency of LOH than negative ones at locus D13S260 and D6S497 suggesting that the target of HPV in esophageal cancer might serve as candidate genes at these two loci. In addition,this result also indicated that HPV might be a high-risk factor for esophageal cancer in Sichuan area with a high incidence of this cancer.</p>

A complete screen for mutations of the rhodopsin gene in a panel of Chinese patients with autosomal dominant retinitis pigmentosa / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the prevalence of rhodopsin (RHO) mutations and the genotype-phenotype relationships in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) by conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing.</p><p><b>METHODS</b>We have screened the five coding exons and splice sites of RHO gene in 27 probands who had no relativity from Chinese ADRP families and 100 normal controls to identify disease-associated mutations, using CSGE and direct DNA sequencing. Family members of some probands with disease-associated mutations were also genotyped to determine whether the RHO mutations segregated with retinitis pigmentosa (RP) in their families.</p><p><b>RESULTS</b>Two RHO mutations, Pro347Leu and Pro327 (1-bp del), were identified separately in two families, thus the frequency of RHO mutations among this set of Chinese ADRP families is about 7.4% (2/27). Pro347Leu mutation was found in one ADRP proband as well as three her children who also had RP. She had relatively early onset at about 17 years. The only one child without this mutation had no symptom or sign of RP at age of 34. Pro327 (1-bp del) was identified in a late-onset ADRP patient, who appeared night blindness around 30 years old and in her fifties electroretinogram (ERG) has been flat in both scotopic and photopic phases. Family analysis showed that this mutation also existed in her younger daughter and her elder sister, both of them also had RP. Three other family members were genotypically and phenotypically normal. Neither of the two mutations was detected in 100 normal controls.</p><p><b>CONCLUSIONS</b>The frequency of RHO mutations in Chinese patients was lower than that in Europe and North America. The phenotype of the patients with Pro347Leu corresponded to type 1 ADRP, with severe rod degeneration and some cone preservation later, while the phenotype of the patients carrying Pro327 (1-bp del) corresponded to type 2 ADRP, with a concomitant loss of rod and cone visual function. CSGE was found to be a sensitive, simple, and practical method for the screening of a large number of samples under highly reproducible conditions, and could be utilized in routine molecular diagnostic laboratories.</p>