Quantile regression and empirical likelihood for the analysis of longitudinal data with monotone missing responses due to dropout,with applications to quality of life measurements from clinical trials

The analysis of quality of life (QoL) data can be challenging due to the skewness of responses and the presence of missing data. In this paper, we propose a new weighted quantile regression method for estimating the conditional quantiles of QoL data with responses missing at random. The proposed method makes use of the correlation information within the same subject from an auxiliary mean regression model to enhance the estimation efficiency and takes into account of missing data mechanism. The asymptotic properties of the proposed estimator have been studied and simulations are also conducted to evaluate the performance of the proposed estimator. The proposed method has also been applied to the analysis of the QoL data from a clinical trial on early breast cancer, which motivated this study.     

De novo truncating mutation in SCN1A as a cause of febrile seizures plus (FS+)

SCN1A is one of the most relevant epilepsy genes. In general, de novo severe mutations, such as truncating mutations, lead to a classic form of Dravet syndrome (DS), while missense mutations are associated with both DS and milder phenotypes within the GEFS+ spectrum, however, these phenotype‐genotype correlations are not entirely consistent. Case report. We report an 18‐year‐old woman with a history of recurrent febrile generalized tonic‐clonic seizures (GTCS) starting at age four months and afebrile asymmetric GTCS and episodes of arrest, suggestive of focal impaired awareness seizures, starting at nine months. Her psychomotor development was normal. Sequencing of SCN1A revealed a heterozygous de novo truncating mutation (c.5734C>T, p.Arg1912X) in exon 26. Conclusion. Truncating mutations in SCN1A may be associated with milder phenotypes within the GEFS+ spectrum. Accordingly, SCN1A gene testing should be performed as part of the assessment for sporadic patients with mild phenotypes that fit within the GEFS+ spectrum, since the finding of a mutation has diagnostic, therapeutic and genetic counselling implications.     

Analysis of Heterozygous BRCA1 5382ins Founder Mutation in a Cohort of Egyptian Breast Cancer Female Patients Using Pyrosequencing Technique

Background: Up to half of the heritable mutations in breast cancer (BC) are attributed to BRCA1 and BRCA2 genes. The mutation prevalence is variable based on ethnicity and may be influenced by founder mutations. The aim of this pilot study is to determine for the first time, the prevalence of BRCA1 5382insC founder mutation in a cohort of Egyptian familial breast cancer patients (FBC). Methods: Female patients were selected to have familial type of breast cancer. Twenty healthy females were included as a control group. Peripheral blood samples were withdrawn from all studied females and were analyzed for BRCA1 5382insC founder mutation detection using pyrosequencing technique. Results: Eighty Egyptian FBC females were eligible to be enrolled in the study with a mean age of 48.31 ± 10.97years.We found a BRCA1 5382insC mutation carrier frequency of 5% of total studied FBC patients (4 out of 80 patients) with 95% confidence interval (1.61-12.99). There was a high statistical significant difference between carriers and non-carriers concerning the number of affected family members by BC, (p=0.001).  Conclusion: BRCA1 5382insC founder mutation is not uncommon among Egyptian FBC females. The carrier frequency is comparable to that reported worldwide; however it is lower than those from previous Egyptian studies using different molecular techniques. The strong association between the mutation and the number of affected family members suggest wider screening of the mutation among high risk families using the reliable pyrosequencing technique.     

Evaluation of mutagenic,recombinogenic and carcinogenic potential of (+)-usnic acid in somatic cells of Drosophila melanogaster

The main of this study was to evaluate the mutagenic and carcinogenic potential of (+) – usnic acid (UA), using Somatic Mutation and Recombination Test (SMART) and the test for detecting epithelial tumor clones (wts) in Drosophila melanogaster. Larvae from 72 ± 4 h from Drosophila were fed with UA (5.0, 10.0 or 20.0 mM); urethane (10.0 mM) (positive control); and solvent (Milli-Q water, 1% Tween-80 and 3% ethanol) (negative control). ST cross produced increase in total mutant spots in the individuals treated with 5.0, 10.0 or 20.0 mM of UA. HB cross produced spot frequencies in the concentration of 5.0 mM that were higher than the frequency for the same concentration in the ST cross. In the highest concentrations the result was negative, which means that the difference observed can be attributed, in part, to the high levels of P450, suggesting that increasing the metabolic capacity maximized the toxic effect of these doses. In the evaluation of carcinogenesis using the wts test, the results obtained for the same concentrations of UA show a positive result for the presence of tumors when compared to the negative control. We conclude that UA has recombinogenic, mutagenic and carcinogenic effects on somatic cells in D. melanogaster.     

Association of gBRCA1/2 mutation locations with ovarian cancer risk in Japanese patients from the CHARLOTTE study

Whether germline (g) breast cancer susceptibility gene (BRCA) mutations are located within or outside the ovarian cancer cluster region (OCCR) (1380‐4062 bp for gBRCA1, and between 3249‐5681 bp and 6645‐7471 bp for gBRCA2) may influence risk variations for ovarian cancers. This ad hoc analysis of the CHARLOTTE epidemiological study in Japan assessed the distribution of gBRCA1/2 mutations in patients with newly diagnosed ovarian cancer, and investigated an association between gBRCA1/2 mutation locations and ovarian cancer risk. Differences in patient background and clinical characteristics in subgroups stratified by gBRCA1/2 mutation locations were also evaluated. We analyzed the data of 93 patients (14.7%) from the CHARLOTTE study who were positive for gBRCA1/2 mutations. After excluding 16 cases with L63X founder mutation, 28 (65.1%) of gBRCA1 mutations were within the OCCR. Of 30 gBRCA2 mutations, 15 (50.0%) were within the OCCR. Of 27 patients (one patient excluded for unknown family history) with gBRCA1 mutations located in the OCCR, 11 (40.7%) had a family history of ovarian cancer; the proportion of patients with a family history of ovarian cancer and gBRCA1 mutations outside the OCCR was lower (13.3%). Sixty percent of patients with gBRCA1 mutations outside the OCCR had a family history of breast cancer; the proportion of patients with a family history of breast cancer and gBRCA1 mutations within the OCCR was relatively lower (33.3%). Understanding the mutation locations may contribute to more accurate risk assessments of susceptible individuals and early detection of ovarian cancer among gBRCA mutation carriers.     

Molecular profiling of Chinese R-CHOP treated DLBCL patients: Identifying a high-risk subgroup

Diffuse large B-cell lymphoma (DLBCL) is a clinically aggressive and heterogenous disease. Although most patients can be cured by immunochemotherapy, 30% to 40% patient will ultimately develop relapsed or refractory disease. Here, we investigated the molecular landscapes of patients with diverse responses to R-CHOP. We performed capture-based targeted sequencing on baseline samples of 105 DLBCL patients using a panel consisting of 112 lymphoma-related genes. Subsequently, 81 treatment-naïve patients with measurable disease and followed for over 1 year were included for survival analysis. Collectively, the most commonly seen mutations included IGH fusion (69%), PIM1(33%), MYD88 (29%), BCL2 (29%), TP53 (29%), CD79B (25%) and KMT2D (24%). Patients with TP53 mutations were more likely to have primary refractory disease (87.0% vs 50.0%, P = .009). For those with TP53 disruptive mutations, 91.7% patients were in the primary refractory group. Interestingly, BCL-2 somatic hypermutation was only seen in patients without primary refractory disease (P = .014). In multivariate analysis, BCL-2 amplification (hazard ratio [HR] = 2.94, P = .022), B2M mutation (HR = 2.99, P = .017) and TP53 mutation (HR = 3.19, P < .001) were independently associated with shorter time to progression (TTP). Furthermore, TP53 mutations was correlated with worse overall survival (P = .049). Next, we investigated mutation landscape in patients with wild-type (WT) TP53 (n = 58) and found that patients harboring MYD88 L265P had significantly inferior TTP than those with WT or non-265P (P = .046). Our study reveals the mutation spectrum of treatment-naive Chinese DLBCL patients. It also confirms the clinical significance of TP53 mutations and indicates the prognostic value of MYD88 L265P in TP53 WT patients.