Cloning And Identification Of CDNA Fragments Related To Human Esophageal Cancer

Esophageal cancer (EC) is one of the most common fatal malignant diseases in China. Thus, the studies on EC have always been one of the major tasks in cancer research in China. Previous studies suggested that many tumor suppressor genes and oncogenes are involved in the initiation and development of EC. However, no gene directly associated with EC has been found. Searching for such genes, whose inactivation or deletion will induce the carcinogenesis in the esophagus, is of great significance in the basic and clinical study on EC.The effective technique of mRNA differential display with our long primers instead of the short ones was used in our study. By comparing the differential gene expression between normal esophageal epithelia (2 normal, 1 adjacent tissue) and EC (2 primary squamous cell carcinoma), differential fragments were isolated, sequenced and identified by RT-PCR and Northern blot hybridization, and subsequently, 5' RACE was used to explore their full-length cDNA.Eighteen differential fragments were isolated and identified, 13 of which were expressed in normal esophageal epithelia but not in EC (assigned as normal esophageal gene, NEG), while 5 were expressed in EC but not in normal esophageal epithelia (assigned as mutated esophageal gene, MEG). 4 NEG fragments were found no remarkable similarity to the known sequences in the homology analysis with the public database of GenBank (of NLM in USA). These 4 fragments which may represent novel genes were assigned as esophageal cancer related gene (ECRG) 1 to 4. The other 14 fragments were homologues of 12 known genes or cDNAs, respectively, including those reported to be associated with tumor, such as GAPDH (glyceraldehyde-3-phosphate dehydrogenase) gene, α-1 collagen type I gene, cytochrome b561...