Lanes 1, 3, 6, 8 are uncut 181 bp products of blood (b) and tumor (t) samples of E189 and E199, respectively
Lanes 1, 3, 6, 8 are uncut 181 bp products of blood (b) and tumor (t) samples of E189 and E199, respectively. of mutations. Unexpectedly, among 10 intronic mutations, eight cases harbored a similar mutation: GC substitution in intron 6 (nucleotide 12759, GenBankNC_000017). These were additionally confirmed by the RFLP technique. Comparable mutations were also detected in their matched blood samples using RFLP and direct sequencing, which suggested germline mutations. There was Cephalomannine no significant correlation between risk habits andp53mutation frequency. CONCLUSION: A proportion of Thai ESCC patients harbored specific intronicp53mutations, which might be germline mutations. Further studies are needed Cephalomannine to explore this novel finding. Keywords:Esophageal cancer, Squamous cell Cephalomannine carcinoma,p53gene, Germline mutation, Mutation, Intron == INTRODUCTION == Esophageal cancer is the eighth most common cancer worldwide, and there were 462 000 new cases in 2002[1]. It is a disease of high mortality, and ranks as the sixth most common cause of cancer death. There is a marked variation in incidence in different regions of the world; a 20-fold difference is observed between high-risk China and low-risk Western Africa. Other areas of moderately high risk are Southern and Eastern Africa, South-Central Asia, and Japan[1]. It seems that environmental carcinogens are responsible for these geographic differences and the different histological types. Tobacco and alcohol use are the main risk factors in Europe and North America[2,3], and other factors including betel chewing, Cephalomannine hot beverages, fermented food, nutritional deficiencies or familial predisposition can be responsible for high rates in other high- or moderate-risk regions[4-7]. The incidence of esophageal cancer in Thailand is usually relatively low when one considers the country-wide estimates, with an age-standardized incidence rate (ASR) of 4.7 per 100 000 males in 1999[8]. However, the incidence is usually exceptionally high in Songkhla province in Southern Thailand, with an ASR of 8.1 per 100 000 males, which is close to worldwide incidence. In this region, oral cancer is usually event more prevalent, with the highest incidence (ASR 9.4 per 100 000 males) compared to other regions of the country. Most esophageal cancer cases in Thailand are squamous cell carcinomas. In our previous case-control study, alcohol consumption, cigarette smoking and betel quid chewing were found to be strong risk factors for esophageal squamous cell carcinoma (ESCC)[9]. Thep53tumor suppressor gene is an important gene in cell cycle regulation and apoptosis. Mutations in thep53gene have been implicated as crucial events in the development of various cancers, including ESCC[10], and they have Rabbit Polyclonal to PSEN1 (phospho-Ser357) been identified as a vulnerable target for crucial DNA damage. Analysis ofp53mutations in various human cancers has denoted a characteristic mutational pattern that is related to specific endogenous as well as exogenous carcinogen-related brokers; a finding that has given rise to the term mutagen fingerprints in DNA[11]. p53mutations in ESCC from Thailand have been reported by two groups in 1997 and 2000[12,13]. However, the numbers of cases were small and the relationship between mutations and risk habits were not explicitly evaluated. Here, we analyzed thep53mutation profile of a larger sample set (165 cases) of ESCC using single-strand conformation polymorphism (SSCP) analysis and direct sequencing. In addition, the relationship between mutation frequency and risk habits, namely alcohol consumption, cigarette smoking and betel quid chewing, was examined. == MATERIALS AND METHODS == == Patients and samples == Patients who were diagnosed with ESCC and treated at Songklanagarind Hospital during 1999-2005 were considered as candidates for the study. The study was approved by the Ethics Committee of the Faculty of Medicine, Prince of Songkla University, and informed consent was obtained from the patients. Data concerning detailed histories of tobacco use, alcohol consumption and betel chewing were obtainedviaface-to-face interviews using structured questionnaires. Only cases with available fresh-frozen tissue samples were included. Tissue samples were obtained from biopsy or surgical resection specimens, snapped frozen and stored at -80C until DNA extraction. All of the cases were primary tumors that had not been treated with radiation or chemotherapy. == Polymerase chain reaction-SSCP analysis == DNA was extracted from.