Familial colorectal cancer type X (FCCTX) is characterized by clinical features of hereditary non-polyposis colorectal cancer with a yet undefined genetic background. Here we identify the SEMA4A p.Val78Met germline mutation in an Austrian kindred with FCCTX, using an integrative genomics strategy. Compared with wild-type protein, SEMA4AV78M demonstrates significantly increased MAPK/Erk and PI3K/Akt signalling as well as cell cycle progression of SEMA4A-deficient HCT-116 colorectal cancer cells. In a cohort of 53 patients with FCCTX, we depict two further SEMA4A mutations, p.Gly484Ala and p.Ser326Phe and the single-nucleotide polymorphism (SNP) p.Pro682Ser. This SNP is highly associated with the FCCTX phenotype exhibiting increased risk for colorectal cancer (OR 6.79, 95% CI 2.63 to 17.52). Our study shows previously unidentified germline variants in SEMA4A predisposing to FCCTX, which has implications for surveillance strategies of patients and their families.

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Despite achieving complete remission after intensive therapy, most patients with cytogenetically normal (CN) AML relapse due to the persistence of submicroscopic residual disease. In this pilot study, we hypothesized that detection of leukemia-specific mutations following consolidation treatment using a targeted parallel sequencing approach predicts relapse. We included 34 AML patients of whom diagnostic material and remission bone marrow slides after at least one cycle of consolidation were available. Isolated DNA was screened for mutations in 19 genes using an Ion Torrent sequencing platform. Furthermore, the variant allelic frequency of distinct mutations was validated by digital PCR and sequencing using a barcoding approach. Twenty-seven out of 34 patients could be analyzed for mutation clearance. We identified 68 somatic mutations at diagnosis (median, 3 mutations per patient; range 1-5) and 22 of these were still detected in 16 patients after consolidation therapy with a reliable sensitivity of 0.5% (median, 1 mutation; range 0-3). The most frequent noncleared mutations were found in DNMT3A. However, as persistence of these mutations has recently been shown to be without any impact on relapse risk, we performed survival and relapse risk analysis excluding DNMT3A mutations. Importantly, persistence of non-DNMT3A mutations was associated with a higher risk of AML relapse (7/8 pts versus 6/19 pts; P = .013) and with a shorter relapse-free survival (333 days vs. not reached; log-rank P = .0219). Detection of residual disease by routine targeted parallel sequencing proved feasible and effective as persistence of somatic mutations other than DNMT3A were prognostic for relapse in CN AML.

Multiple myeloma (MM) is a malignant clonal expansion of plasma cells in the bone marrow and belongs to the mature B-cell neoplams. The pathogenesis of MM is associated with constitutive NF-κB activation. However, genetic alterations causing constitutive NF-κB activation are still incompletely understood. Since A20 (TNFAIP3) is a suppressor of the NF-κB pathway and is frequently inactivated in various lymphoid malignancies, we investigated the genetic and epigenetic properties of A20 in MM. In total, of 46 patient specimens analyzed, 3 single base pair exchanges, 2 synonymous mutations and one missense mutation were detected by direct sequencing. Gene copy number analysis revealed a reduced A20 gene copy number in 8 of 45 (17.7%) patients. Furthermore, immunohistochemical staining confirmed that A20 expression correlates with the reduction of A20 gene copy number. These data suggest that A20 contributes to tumor formation in a significant fraction of myeloma patients.