Comparison of targeted next-generation sequencing and Sanger sequencing for the detection of <Emphasis Type="Italic">PIK3CA</Emphasis> mutations in breast cancer

Background

Phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha, PIK3CA, is one of the most frequently mutated genes in breast cancer, and the mutation status of PIK3CA has clinical relevance related to response to therapy.The aim of our study was to investigate the mutation status of PIK3CA gene and to evaluate the concordance between NGS and SGS for the most important hotspot regions in exon 9 and 20, to investigate additional hotspots outside of these exons using NGS, and to correlate the PIK3CA mutation status with the clinicopathological characteristics of the cohort.

Methods

In the current study, next-generation sequencing (NGS) and Sanger Sequencing (SGS) was used for the mutational analysis of PIK3CA in 186 breast carcinomas.

Results

Altogether, 64 tumors had PIK3CA mutations, 55 of these mutations occurred in exons 9 and 20. Out of these 55 mutations, 52 could also be detected by Sanger sequencing resulting in a concordance of 98.4 % between the two sequencing methods. The three mutations missed by SGS had low variant frequencies below 10 %. Additionally, 4.8 % of the tumors had mutations in exons 1, 4, 7, and 13 of PIK3CA that were not detected by SGS. PIK3CA mutation status was significantly associated with hormone receptor-positivity, HER2-negativity, tumor grade, and lymph node involvement. However, there was no statistically significant association between the PIK3CA mutation status and overall survival.

Conclusions

Based on our study, NGS is recommended as follows: 1) for correctly assessing the mutation status of PIK3CA in breast cancer, especially for cases with low tumor content, 2) for the detection of subclonal mutations, and 3) for simultaneous mutation detection in multiple exons.

     

Increased thrombin generation in splanchnic vein thrombosis is related to the presence of liver cirrhosis and not to the thrombotic event

Introduction

In recent years there have been increasing evidence associating liver disease with hypercoagulability, rather than bleeding. The aim of the study was to evaluate the haemostatic potential in patients with liver disease.

Patients and methods

We measured thrombin generation in the presence and absence of thrombomodulin in patients with portal vein thrombosis (PVT, n = 47), Budd-Chiari syndrome (BCS, n = 15) and cirrhosis (n = 24) and compared the results to those obtained from healthy controls (n = 21). Fifteen patients with PVT and 10 patients with BCS were treated with warfarin and were compared to an equal number of patients with atrial fibrillation matched for prothrombin time-international normalized ratio. We assessed resistance to thrombomodulin by using ratios [marker measured in the presence/absence of thrombomodulin].

Results

There were no differences in thrombin generation between patients on warfarin treatment and their controls. Cirrhotic patients generated more thrombin in the presence of thrombomodulin and exhibited thrombomodulin resistance compared to controls [p = 0.006 for endogenous thrombin potential (ETP) and p < 0.001 for peak thrombin and both ratios ETP and peak] and patients with non-cirrhotic PVT (p = 0.001, p = 0.006, p < 0.001, p < 0.001 for ETP, peak, ratio ETP, ratio peak, respectively). The patients with cirrhotic PVT exhibited higher ETP (p = 0.044) and peak (p = 0.02) in the presence of thrombomodulin than controls, as well as thrombomodulin resistance (ETP and peak ratios: p = 0.001).

Conclusions

Hypercoagulability and thrombomodulin resistance in patients with cirrhosis were independent of the presence of splanchnic vein thrombosis. The hypercoagulability in patients with cirrhotic PVT could have implications for considering longer or more intensive treatment with anticoagulants in this group.     

Colorectal neoplasia in patients with primary sclerosing cholangitis undergoing liver transplantation: a Nordic multicenter study

Abstract Objective. Several studies have implicated primary sclerosing cholangitis (PSC) as an additional risk factor for colorectal neoplasia in inflammatory bowel disease (IBD). Some reports have indicated that the risk is even higher in PSC-IBD patients after liver transplantation (Ltx), but this issue is controversial. We aimed to compare the risk of colorectal neoplasia in PSC-IBD patients before and after Ltx and to identify risk factors for colorectal neoplasia post-transplant. Material and methods. In a multicenter study within the Nordic Liver Transplant Group, we assessed the risk of colorectal neoplasia by using the competing risk regression analysis. Results. Among the 439 PSC patients included, 353 (80%) had IBD at the time of Ltx and 15 (3%) patients developed de novo IBD post-Ltx. The median duration of IBD was 15 (0-50) years at the time of Ltx and follow-up after Ltx was 5 (0-20) years. Ninety-one (25%) PSC-IBD patients developed colorectal neoplasia. The cumulative risk of colorectal neoplasia was higher after than before Ltx (HR: 1.9, 95% CI: 1.3-2.9, p = 0.002). A multivariate analysis demonstrated aminosalicylates and ursodeoxycholic acid as significantly associated with an increased risk of colorectal neoplasia post-Ltx. Duration and activity of IBD did not significantly affect the risk of neoplasia. Conclusion. The even higher risk of colorectal neoplasia in PSC-IBD patients after when compared with that of before Ltx underscores the importance of regular surveillance colonoscopies post-Ltx. The association of aminosalicylates and ursodeoxycholic acid to the development of colorectal neoplasia after Ltx should be further investigated.     

Association of in utero sensitization to Schistosoma haematobium with enhanced cord blood IgE and increased frequencies of CD5- B cells in African newborns

This study investigated in utero priming as a consequence of maternal parasitic infections. Cord blood plasma samples of 63 African newborns were assessed by enzyme-linked immunosorbent assay for their content of total and schistosome-specific or filaria-specific IgE and IgG4. The frequencies of lymphocyte phenotypes in cord blood were also determined by using flow cytometry, and were compared with those of European newborns. We found significantly increased schistosome soluble egg antigen (SEA)-specific IgE in cord plasma of those born to mothers with schistosome infections and correlations between fetal and maternal SEA-specific and filaria antigen-specific IgE. These data are evidence for in utero priming of the fetal immune system to maternal helminth infections. Furthermore, we show significantly enhanced percentages of CD5- B cells in African newborns cord blood compared with Europeans, which is consistent with earlier maturation of the African fetal immune system.