Evolutionary evidence of the effect of rare variants on disease etiology

Gorlov IP, Gorlova OY, Frazier ML, Spitz MR, Amos CI. Evolutionary evidence of the effect of rare variants on disease etiology. The common disease/common variant hypothesis has been popular for describing the genetic architecture of common human diseases for several years. According to the originally stated hypothesis, one or a few common genetic variants with a large effect size control the risk of common diseases. A growing body of evidence, however, suggests that rare single‐nucleotide polymorphisms (SNPs), i.e. those with a minor allele frequency of less than 5%, are also an important component of the genetic architecture of common human diseases. In this study, we analyzed the relevance of rare SNPs to the risk of common diseases from an evolutionary perspective and found that rare SNPs are more likely than common SNPs to be functional and tend to have a stronger effect size than do common SNPs. This observation, and the fact that most of the SNPs in the human genome are rare, suggests that rare SNPs are a crucial element of the genetic architecture of common human diseases. We propose that the next generation of genomic studies should focus on analyzing rare SNPs. Further, targeting patients with a family history of the disease, an extreme phenotype, or early disease onset may facilitate the detection of risk‐associated rare SNPs.     

Biological features and outcome of diffuse large B-cell lymphoma associated with hepatitis C virus in elderly patients: Results of the prospective ‘Elderly Project’ by the Fondazione Italiana Linfomi

Up to 10%–15% of diffuse large B-cell lymphoma (DLBCL) are related to hepatitis C virus (HCV) infection, in particular in elderly patients. The Fondazione Italiana Linfomi has recently published a multicentre prospective observational study, the ‘Elderly Project’, on the outcome of DLBCL in patients aged ≥65 years, evaluated using a simplified comprehensive geriatric assessment. The aim of this study was to compare biological and clinical features of HCV positive (HCV+) with HCV negative (HCV−) cases. A total of 89 HCV+ patients were identified out of 1095 evaluated for HCV serology (8.1%). The HCV+ patients were older, less fit, and had frequent extranodal involvement. The cell-of-origin determination by Nanostring showed that HCV+ cases less frequently had an activated B-cell profile compared to HCV− patients (18% vs. 43%). In all, 86% of HCV+ patients received rituximab-cyclophosphamide, doxorubicin, vincristine (Oncovin) and prednisone (R-CHOP)-like immunochemotherapy. Grade 3–4 liver toxicity occurred in 3% of cases. Among centrally reviewed cases confirmed as DLBCL, the 3-year overall survival of HCV+ patients was very similar to HCV− (63% vs. 61%, p = 0.926). In all, 20 HCV+ patients were treated with direct-acting antiviral agents (DAAs), with good tolerance and sustained virological response in all cases. The 3-year progression-free survival for this subgroup was excellent (77%), suggesting DAAs' possible role in reducing the risk of relapse by eliminating the viral trigger.     

The elderly prognostic index predicts early mortality in older patients with diffuse large B-cell lymphoma. An ad hoc analysis of the elderly project by the Fondazione Italiana Linfomi

The Elderly Prognostic Index (EPI) is based on the integration of a simplified geriatric assessment, hemoglobin levels and International Prognostic Index and has been validated to predict overall survival in older patients with diffuse large B-cell lymphoma (DLBCL). In this study, we evaluated the ability of EPI to predict the risk of early mortality. This study included all patients registered in the Elderly Project for whom treatment details and a minimum follow-up of 3 months were available. Three main treatment groups were identified based on the anthracycline amount administered: cases receiving >70% of the theoretical anthracyclines dose (Full Dose [FD] group), ≤70% (Reduced Dose [RD]) and palliative therapy (PT; no anthracyclines). The primary endpoint was early mortality rate, defined as death for any cause occurring within 90 days from diagnosis. We identified 1150 patients with a median age of 76 years (range 65–94). Overall, 69 early deaths were observed, accounting for 19% of all reported deaths. The cumulative rate of early mortality at 90 days was 6.0%. Comparing early with delayed deaths, we observed a lower frequency of deaths due to lymphoma progression (42% vs. 75%; p < 0.001) and a higher frequency due to toxicity and infections (22% vs. 4%, p < 0.001, and 22% vs. 3%, p < 0.001, respectively) for early events. A multivariable logistic analysis on 931 patients (excluding PT) confirmed an independent association of high-risk EPI (odds ratio [OR] 3.60; 95% confidence interval [CI] 1.15–11.2) and bulky disease (OR 2.08; 95% CI 1.09–3.97) with the risk of early mortality. The cumulative incidence of early mortality for older patients with DLBCL is not negligible and is mainly associated with non-lymphoma related events. For patients receiving anthracyclines, high-risk EPI and bulky disease are associated with a higher probability of early mortality.