脊髓小脑共济失调2型家系ATXN2基因中间重复病例表型与分子遗传学特征

目的探讨脊髓小脑共济失调2型(SCA2)致病基因ATXN2异常等位基因中间重复个体的表型和分子遗传学特点。方法针对2005—2018年中日友好医院神经科运动障碍与神经遗传病研究中心收集的1383个常染色体显性遗传共济失调家系的先证者和部分家系成员,采用荧光标记毛细管电泳片段分析方法进行动态突变检测,对携带ATXN2基因中间重复的个体进行临床表型和遗传特征分析。结果共检出163个家系(包含先证者和家系成员共203人)携带异常扩展的ATXN2基因CAG重复序列,其中93个家系中有107例的异常扩展等位基因重复次数在29~34次之间。在其中的20个亲子对中,父系遗传16个,异常等位基因的代间扩展增加0~28次,母系遗传4个,异常等位基因的代间扩展增加0~4次。结论对于临床拟诊SCA2家系患者,需对其亲代或成年子代个体进行ATXN2基因检测,以免漏诊。动态突变基因检测有助于识别中间重复的个体,对明确家系致病基因和遗传咨询至关重要。     

Differential Expression of PD-L1 Between Sporadic and VHL-Associated Hereditary Clear-Cell Renal Cell Carcinoma and Its Correlation With Clinicopathological Features

Background

Programmed death ligand-1 (PD-L1) is a potential predictive biomarker for immunotherapy in several malignancies. However, the expression level and clinical significance of PD-L1 in von Hippel–Lindau (VHL)-associated hereditary clear-cell renal cell carcinoma (ccRCC) remain unclear.

Incidence of T790M in Patients With NSCLC Progressed to Gefitinib,Erlotinib, and Afatinib: A Study on Circulating Cell-free DNA

BackgroundInsights into the mechanism of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) could provide important information for further patient management, including the choice of second-line treatment. The EGFR T790M mutation is the most common mechanism of resistance to first- and second-generation EGFR TKIs. Owing to its biologic relevance in the response of non–small-cell lung cancer (NSCLC) to the selective pressure of treatment, the present study investigated whether the occurrence of T790M at progression differed among patients receiving gefitinib, erlotinib, or afatinib.Patients and MethodsThe present retrospective study included patients with NSCLC with an EGFR activating mutation, who had received gefitinib, erlotinib, or afatinib as first-line treatment. Plasma samples for the analysis of cell-free DNA were taken at disease progression and analyzed using a digital droplet polymerase chain reaction EGFR mutation assay.ResultsA total of 83 patients were enrolled; 42 had received gefitinib or erlotinib and 41afatinib. The patient characteristics were comparable across the 2 groups. The median time to progression (TTP) was 14.4 months for the gefitinib and erlotinib group and 10.2 months for the afatinib group (P = .09). Of the 83 patients, 47 (56.6%) were positive for the T790M in plasma. A greater incidence of T790M was observed in patients with progression during gefitinib or erlotinib therapy compared with patients treated with afatinib (33 [79%] vs. 14 [34%], respectively; odds ratio, 7.1; 95% confidence interval, 2.7-18.5; P = .0001).ConclusionsAlthough gefitinib, erlotinib, and afatinib showed a comparable TTP in patients receiving first-line therapy, the incidence of T790M differed among them, as demonstrated by the present study, which could have implications for the choice of second-line treatment.     

易感基因CELSR2与汉族青少年特发性脊柱侧凸的相关性研究

目的 :在中国汉族人群中验证易感基因CELSR2与青少年特发性脊柱侧凸(adolescent idiopathic scoliosis,AIS)发病的相关性。方法:利用等位基因特异性多重连接酶检测反应在1794例AIS患者和1040例正常对照人群中对既往报道的CELSR2基因的易感位点rs141489111、rs6698843和rs2281894进行基因分型。同时在本中心全基因组数据库中分析CELSR2基因其他单核苷酸多态性位点(SNP)的基因分型信息。术中收集45例AIS患者(AIS组)和10例年龄匹配的脊柱外伤患者(对照组)的椎旁肌,比较两组椎旁肌中基因表达水平的差异。利用卡方检验分析组间SNP位点最小等位基因频率差异,采用T检验对组间的基因表达水平进行统计分析。结果:1794例AIS患者和1040例正常对照人群中,rs141489111位点未检测到突变,所有研究对象基因型均为GG。SNP位点rs6698843和rs2281894的基因型及等位基因频率在AIS和正常对照人群间未见显著性差异(P0.05)。GWAS数据库显示其他7个位于CELSR2基因上的SNP位点与AIS亦无显著相关性(P0.05)。CELSR2基因在AIS组和对照组椎旁肌的表达水平无显著性差异(P0.05)。结论:既往报道的易感基因CELSR2上的突变位点和多态性位点均未在中国汉族人群中得到验证,AIS患者椎旁肌组织中CELSR2表达未见明显异常。CELSR2可能与汉族AIS的发生无关。     

Tumor Protein p53 and K-ras Gene Mutations in Peruvian Patients with Gallbladder Cancer

Background: Recent studies have shown that genetic alterations are associated with the effect of patient geographiclocation on gallbladder cancer development. Peru has a high incidence of gallbladder cancer, but causative factorshave not yet been identified. We examined the frequency of mutations in TP53 and K-ras genes in Peruvian patientswith gallbladder cancer, and compared this with data from Bolivia, Hungary, Chile, and Japan, which have a highgallbladder cancer incidence. Methods: DNA was extracted from formalin-fixed paraffin-embedded gallbladder tissuesections of 30 gallbladder cancer patients (9 men and 21 women) obtained using microdissection. Mutations in exons5 to 8 of TP53 and codons 12, 13, and 61 of K-ras were examined using direct sequencing. Results: TP53 mutationswere observed in 10 (33.3%) of patients, but K-ras mutations were absent. Nine (90%) TP53 mutations were pointmutations (7 missense and 2 silent mutations), and the most frequent substitution was a G:C to A:T transition. G:C toA:T transitions at the CpG site or G:C to T:A transversions were found in one patient each. No significant differenceswere found in the frequency of TP53 and K-ras mutations among patients in the 5 countries. Conclusions: Our findingssuggest that endogenous mechanisms and exogenous carcinogens may affect the carcinogenic process in Peruviangallbladder cancer patients, similar to that in Bolivian patients. Further studies with a larger sample size are neededto clarify these findings.     

Tumor-specific prognosis of mutation-positive patients with head and neck paragangliomas

BackgroundGenetic testing to identify succinate dehydrogenase (SDH) mutations in patients with head and neck paraganglioma (HNP) has been in clinical practice for more than a decade. However, the recurrence and metachronous tumor occurrence risks in surgically treated mutation-positive patients are not well studied.MethodsClinical and procedural details of consecutive patients who underwent excision for HNP from January 1996 to October 2016 were retrospectively reviewed. End points included recurrence, metachronous tumor detection, and mortality. Germline DNA was tested to identify mutations in SDHx genes. Patients were divided into three groups on the basis of genetic testing: group I, positive; group II, negative; and group III, unknown or offered but not tested.ResultsHNP was diagnosed in 268 patients, 214 (147 female; mean age, 47 years) included in this study. Directed genetic testing was performed in 68; mutations were detected in SDH in 47 (69%), a majority SDHD. In group I, 47 patients had 64 procedures for 81 tumors (52 carotid body tumors [CBTs]); 17 (36%) were bilateral, 7 (15%) multiple, 3 (6%) functional, and 7 (15%) malignant. Residual tumor in 10 was significant in 2, managed by radiation therapy and reoperation. Local recurrence was detected in 12 patients (25%) at a median of 8 years; 11 metachronous mediastinal and retroperitoneal paragangliomas were detected in 8 (17%) at a median of 13 years. Systemic metastases occurred in five (10%). Six patients (13%) had more than one recurrence. In group II, 21 patients had 22 procedures for 23 tumors, 17 CBTs. Two (9%) were bilateral and two (9%) malignant. Excision was complete in all with no recurrence or systemic metastasis at last follow-up. For group III, 146 patients underwent 153 procedures for 156 tumors, 95 CBTs; 7 (5%) were bilateral, 2 (1%) multiple, 8 (5%) functional, and 1 (0.6%) malignant. Local recurrence was detected in nine (6%) at a median of 9 years and metachronous HNP in three (2%) at a median of 5 years. Systemic metastases occurred in two (1%). Mortality was 4% in group I and 3% in group III, none procedure or tumor related. Group I (mutation positive) had 10-year overall, recurrence-free, and metachronous tumor-free survival rates of 93%, 69.4%, and 73%, respectively, lower than the other groups (P < .001).ConclusionsBilateral, functional, malignant, recurrent, and metachronous tumors are more common in SDH mutation-positive patients with HNP. Overall survival in patients with HNP is high. Metachronous tumors or local recurrences occur late, and long-term follow-up is necessary.