AIM: To investigate whether whole-exome sequencing may serve as an efficient method to identify known or novel colorectal cancer(CRC) predisposing genes in early-onset or familial CRC cases.METHODS: We performed whole-exome sequencing in 23 Chinese patients from 21 families with nonpolyposis CRC diagnosed at ≤ 40 years of age, or from multiple affected CRC families with at least 1 firstdegree relative diagnosed with CRC at ≤ 55 years of age.Genomic DNA from blood was enriched for exome sequences using the Sure Select Human All Exon Kit, version 2(Agilent Technologies) and sequencing was performed on an Illumina Hi Seq 2000 platform.Data were processed through an analytical pipeline to search for rare germline variants in known or novel CRC predisposing genes.RESULTS: In total, 32 germline variants in 23 genes were identified and confirmed by Sanger sequencing.In 6 of the 21 families(29%), we identified 7 mutations in 3 known CRC predisposing genes including MLH1(5 patients), MSH2(1 patient), and MUTYH(biallelic, 1 patient), five of which were reported as pathogenic.Inthe remaining 15 families, we identified 20 rare and novel potentially deleterious variants in 19 genes, six of which were truncating mutations.One previously unreported variant identified in a conserved region of EIF2AK4(p.Glu738_Asp739insA rgA rg) was found to represent a local Chinese variant, which was significantly enriched in our early-onset CRC patient cohort compared to a control cohort of 100 healthy Chinese individuals scored negative by colonoscopy(33.3% vs 7%, P < 0.001).CONCLUSION: Whole-exome sequencing of early-onset or familial CRC cases serves as an efficient method to identify known and potential pathogenic variants in established and novel candidate CRC predisposing genes.
Jun-Xiao ZhangLei FuRicharda M de VoerMarc-Manuel HahnPeng JinChen-Xi LvEugène TP VerwielMarjolijn JL LigtenbergNicoline HoogerbruggeRoland P KuiperJian-Qiu ShengAd Geurts van Kessel
目的：研究雌激素对结肠癌细胞株COLO205错配修复基因表达的影响。方法：使用半定量RT-PCR和Westernblot,比较在不同浓度雌二醇（estradiol,E2）水平和雌激素受体拮抗剂ICI182.780处理前后结肠癌细胞株COLO205错配修复基因hMLH1和hMSH2的表达差异。并用real time RT-PCR进行验证。结果：E2能上调COLO205细胞株hMLH1基因的表达,这种上调效应发生在转录水平,在E2浓度为10-12~10-8mol/L范围内呈剂量依赖关系,且可被雌激素受体拮抗剂ICI182.780抑制;但E2对COLO205细胞的hMSH2表达没有明显影响。结论：雌激素能够增强结肠癌细胞株COLO205错配修复基因hMLH1的表达,这可能是雌激素预防结肠癌作用的一种新机制。
