Patients with cardiac tumors should undergo surgery in a timely fashion in a specialized center. This holds for both malignant and benign tumors, particularly for atrial myxoma, which can cause serious secondary complications by embolization.

Primary cardiac angiosarcomas are rare tumors with unfavorable prognosis. Pathogenic driver mutations are largely unknown. We therefore analyzed a collection of cases for genomic aberrations using SNP arrays and targeted next-generation sequencing (tNGS) of oncogenes and tumor-suppressor genes. Recurrent gains of chromosome 1q and a small region of chromosome 4 encompassing KDR and KIT were identified by SNP array analysis. Repeatedly mutated genes identified by tNGS were KDR with different nonsynonymous mutations, MLL2 with different nonsense mutations, and PLCG1 with a recurrent nonsynonymous mutation (R707Q) in the highly conserved autoinhibitory SH2 domain in three of 10 cases. PLCg1 is usually activated by Y783 phosphorylation and activates protein kinase C and Ca 2þ -dependent second messengers, with effects on cellular proliferation, migration, and invasiveness. Ectopic expression of the PLCg1-R707Q mutant in endothelial cells revealed reduced PLCg1-Y783 phosphorylation with concomitant increased c-RAF/MEK/ ERK1/2 phosphorylation, increased IP3 amounts, and increased Ca 2þ -dependent calcineurin activation compared with ectopic expressed PLCg1-wild-type. Furthermore, cofilin, whose activation is associated with actin skeleton reorganization, showed decreased phosphorylation, and thus activation after expression of PLCg1-R707Q compared with PLCg1-wild-type. At the cellular level, expression of PLCg1-R707Q in endothelial cells had no influence on proliferation rate, but increased apoptosis resistance and migration and invasiveness in in vitro assays. Together, these findings indicate that the PLCg1-R707Q mutation causes constitutive activation of PLCg1 and may represent an alternative way of activation of KDR/PLCg1 signaling besides KDR activation in angiosarcomas, with implications for VEGF/KDR targeted therapies. Cancer Res; 74(21); 6173-83. Ó2014 AACR.

Protein phosphatase (PP) type 2A is a multifunctional serine/threonine phosphatase that is involved in cardiac excitation–contraction coupling. The PP2A core enzyme is a dimer, consisting of a catalytic C and a scaffolding A subunit, which is targeted to several cardiac proteins by a regulatory B subunit. At present, it is controversial whether PP2A and its subunits play a critical role in end-stage human heart failure. Here we report that the application of purified PP2AC significantly increased the Ca2+-sensitivity (ΔpCa50 = 0.05 ± 0.01) of the contractile apparatus in isolated skinned myocytes of non-failing (NF) hearts. A higher phosphorylation of troponin I (cTnI) was found at protein kinase A sites (Ser23/24) in NF compared to failing myocardium. The basal Ca2+-responsiveness of myofilaments was enhanced in myocytes of ischemic (ICM, ΔpCa50 = 0.10 ± 0.03) and dilated (DCM, ΔpCa50 = 0.06 ± 0.04) cardiomyopathy compared to NF. However, in contrast to NF myocytes the treatment with PP2AC did not shift force-pCa relationships in failing myocytes. The higher basal Ca2+-sensitivity in failing myocytes coincided with a reduced protein expression of PP2AC in left ventricular tissue from patients suffering from ICM and DCM (by 50 and 56% compared to NF, respectively). However, PP2A activity was unchanged in failing hearts despite an increase of both total PP and PP1 activity. The expression of PP2AB56α was also decreased by 51 and 62% in ICM and DCM compared to NF, respectively. The phosphorylation of cTnI at Ser23/24 was reduced by 66 and 49% in ICM and DCM compared to NF hearts, respectively. Our results demonstrate that PP2A increases myofilament Ca2+-sensitivity in NF human hearts, most likely via cTnI dephosphorylation. This effect is not present in failing hearts, probably due to the lower baseline cTnI phosphorylation in failing compared to non-failing hearts.

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F-FDG PET/CT is a valuable tool for the diagnosis of LVAD driveline infection with high diagnostic accuracy. Particularly the use of the metabolic volume yields very high accuracy and performs slightly better than SUVmax.