Heritable predisposition is an important cause of cancer in children and adolescents. Although a large number of cancer predisposition genes and their associated syndromes and malignancies have already been described, it appears likely that there are more pediatric cancer patients in whom heritable cancer predisposition syndromes have yet to be recognized. In a consensus meeting in the beginning of 2016, we convened experts in Human Genetics and Pediatric Hematology/Oncology to review the available data, to categorize the large amount of information, and to develop recommendations regarding when a cancer predisposition syndrome should be suspected in a young oncology patient. This review summarizes the current knowledge of cancer predisposition syndromes in pediatric oncology and provides essential information on clinical situations in which a childhood cancer predisposition syndrome should be suspected.

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Proteasome inhibitors and histone deacetylase (HDAC) inhibitors are novel targeted therapies being evaluated in clinical trials for cutaneous T-cell lymphoma (CTCL). However, data in regard to tumor biology are limited with these agents. In the present study we analyzed the effects of the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) and the proteasome inhibitor bortezomib on human CTCL cells. Four CTCL cell lines (SeAx, Hut-78, MyLa, and HH) were exposed to bortezomib and/ or SAHA at different concentrations. Cell viability was quantified using the MTT assay. In addition, apoptosis and generation of reactive oxygen species were analyzed. Both agents potently inhibited cell viability and induced apoptosis. After 48 h of incubation, IC50 of bortezomib was noted at 8.3 nm, 7.9 nm, 6.3 nm, and 22.5 nm in SeAx, Hut-78, HH, and MyLa cells, respectively. For SAHA, the IC50 values were at 0.6 microm in SeAx cells, 0.75 microm in Hut-78 cells, 0.9 microm in HH cells, and 4.4 microm in MyLa cells. Importantly, combined treatment resulted in synergistic cytotoxic effects, as indicated by Combination indices values <1 using the median effect method of Chou and Talalay. We furthermore found that combined treatment with both agents lead to a decreased proteasome activity, an upregulation of the cell regulators p21 and p27 and increased expression of phosphorylated p38. In addition, we showed that SAHA reduced the vascular endothelial growth factor production of CTCL cells. Our results demonstrate that bortezomib and SAHA synergistically induce apoptosis in CTCL cells and thus provide a rationale for clinical trials of combined proteasome and histone deacetylase inhibition in the treatment of CTCL.

Lytic bone disease is one of the major clinical problems in multiple myeloma (MM) patients and has negative impact both on overall survival and quality of life (1, 2). Myeloma bone disease is characterized by a dysbalance in bone remodeling, caused by enhanced osteoclast activity and decreased bone formation (3,4). In animal models a mutual stimulation has been found between myeloma bone disease and tumor progression (5, 6). Furthermore, the bone marker carboxy-terminal telopeptide of type I-collagen (ICTP) recently proved to be a powerful prognostic marker in MM (1).An increase in receptor activator of nuclear factor kappa B ligand (RANKL) and decrease of osteoprotegerin (OPG) in the bone marrow microenvironment stimulates osteoclast formation and activity in MM (7-9). Additionally, macrophage inflammatory protein-1 alpha (10) is another factor important in attraction of osteoclast precursors. On the other hand, osteoblast activity is strongly reduced in patients with MM (3). Bone formation is impaired through reduced mesenchymal stem cell proliferation and differentiation and inhibition of osteoblast function (11). AbstractLytic bone destruction is a hallmark of multiple myeloma (MM) and is because of an uncoupling of bone remodeling. Secretion of Dickkopf (DKK)-1 by myeloma cells is a major factor which causes inhibition of osteoblast precursors. In this study, the effect of different treatment regimens for MM on serum DKK-1 was evaluated and correlated with the response to treatment in 101 myeloma patients receiving bortezomib, thalidomide, lenalidomide, adriamycin and dexamethasone (AD) or high-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT). At baseline, myeloma patients had increased serum DKK-1 as compared with patients with MGUS (mean 3786 pg ⁄ mL vs. 1993 pg ⁄ mL). There was no difference between previously untreated MM patients and patients at relapse. A significant decrease of DKK-1 after therapy was seen in the following groups: Bortezomib (4059 pg ⁄ mL vs. 1862 pg ⁄ mL, P = 0.016), lenalidomide (11837 pg ⁄ mL vs. 4374 pg ⁄ mL, P = 0.039), AD (1668 pg ⁄ mL vs. 1241 pg ⁄ mL, P = 0.016), and AD + HDCT + ASCT (2446 pg ⁄ mL vs. 1082 pg ⁄ mL, P = 0.001). Thalidomide led to a nonsignificant decrease in DKK-1 (1705 pg ⁄ mL vs. 1269 pg ⁄ mL, P = 0.081). Within all groups, a significant decrease of DKK-1 was only seen in responders (i.e. patients achieving complete remission or partial remission), but not in non-responders. We show for the first time that serum DKK-1 levels decrease in myeloma patients responding to treatment, irrespective of the regimen chosen. These data suggest that myeloma cells are the main source of circulating DKK-1 protein and provide a framework for clinical trials on anti-DKK-1 treatment in MM.

In a 14-year-old boy with polyposis and rectosigmoid carcinoma, we identified a novel POLE germline mutation, p.(Val411Leu), previously found as recurrent somatic mutation in ‘ultramutated’ sporadic cancers. This is the youngest reported cancer patient with polymerase proofreading-associated polyposis indicating that POLE mutation p.(Val411Leu) may confer a more severe phenotype than previously reported POLE and POLD1 germline mutations. The patient had multiple café-au-lait macules and a pilomatricoma mimicking the clinical phenotype of constitutional mismatch repair deficiency. We hypothesize that these skin features may be common to different types of constitutional DNA repair defects associated with polyposis and early-onset cancer.

Heat shock protein 90 (HSP90) is a promising target for tumor therapy. The novel HSP90 inhibitor NVP-AUY922 has preclinical activity in multiple myeloma, however, little is known about effective combination partners to design clinical studies. Multiple myeloma cell lines, OPM-2, RPMI-8226, U-266, LP-1, MM1.S, and primary myeloma cells were exposed to NVP-AUY922 and one of the combination partners histone deacetylase inhibitor NVP-LBH589, suberoylanilide hydroxamic acid (SAHA), melphalan, or doxorubicin, either simultaneously or in sequential patterns. Effects on cell proliferation and apoptosis were determined. Synergistic effects were evaluated using the method of Chou and Talalay. Combined sequential incubation with NVP-AUY922 and SAHA showed that best synergistic effects were achieved with 24 h preincubation with SAHA followed by another 48 h of combination treatment. Combination of NVP-AUY922 with SAHA, NVP-LBH589, melphalan, or doxorubicin resulted in synergistic inhibition of viability, with strong synergy (combination index < 0.3) in the case of melphalan. Importantly, resistance of the RPMI-8226 cell line and relative resistance of some primary myeloma cells against NVP-AUY922 could be overcome by combination treatment. These data show impressive synergistic action of the novel HSP90 inhibitor NVP-AUY922 with melphalan, doxorubicin, NVP-LBH589, and SAHA in multiple myeloma and build the frame work for clinical trials.

Heat shock protein 90 (HSP90) binds and stabilizes numerous proteins and kinases essential for myeloma cell survival and proliferation. We and others have recently demonstrated that inhibition of HSP90 by small molecular mass inhibitors induces cell death in multiple myeloma (MM). However, some of the HSP90 inhibitors involved in early clinical trials have shown limited antitumor activity and unfavorable toxicity profiles. Here, we analyzed the effects of the novel, orally bioavailable HSP90 inhibitor NVP-HSP990 on MM cell proliferation and survival. The inhibitor led to a significant reduction in myeloma cell viability and induced G2 cell cycle arrest, degradation of caspase-8 and caspase-3, and induction of apoptosis. Inhibition of the HSP90 ATPase activity was accompanied by the degradation of MM phospho-Akt and phospho-ERK1/2 and upregulation of Hsp70. Exposure of MM cells to a combination of NVP-HSP990 and either melphalan or histone deacetylase (HDAC) inhibitors caused synergistic inhibition of viability, increased induction of apoptosis, and was able to overcome the primary resistance of the cell line RPMI-8226 to HSP90 inhibition. Combined incubation with melphalan and NVP-HSP990 led to synergistically increased cleavage of caspase-2, caspase-9, and caspase-3. These data demonstrate promising activity for NVP-HSP990 as single agent or combination treatment in MM and provide a rationale for clinical trials.

BACKGROUND Adoptive transfer of EBV-specific T cells can restore specific immunity in immunocompromised patients with EBV-associated complications. METHODS We provide results of a personalized T cell manufacturing program evaluating donor, patient, T cell product, and outcome data. Patient-tailored clinical-grade EBV-specific cytotoxic T lymphocyte (EBV-CTL) products from stem cell donors (SCDs), related third-party donors (TPDs), or unrelated TPDs from the allogeneic T cell donor registry (alloCELL) at Hannover Medical School were manufactured by immunomagnetic selection using a CliniMACS Plus or Prodigy device and the EBV PepTivators EBNA-1 and Select. Consecutive manufacturing processes were evaluated, and patient outcome and side effects were retrieved by retrospective chart analysis. RESULTS Forty clinical-grade EBV-CTL products from SCDs, related TPDs, or unrelated TPDs were generated for 37 patients with refractory EBV infections or EBV-associated malignancies with and without a history of transplantation, within 5 days (median) after donor identification. Thirty-four patients received 1–14 EBV-CTL products (fresh and cryopreserved). EBV-CTL transfer led to a complete response in 20 of 29 patients who were evaluated for clinical response. No infusion-related toxicity was reported. EBV-specific T cells in patients’ blood were detectable in 16 of 18 monitored patients (89%) after transfer, and their presence correlated with clinical response. CONCLUSION Personalized clinical-grade manufacture of EBV-CTL products via immunomagnetic selection from SCDs, related TPDs, or unrelated TPDs in a timely manner is feasible. Overall, EBV-CTLs were clinically effective and well tolerated. Our data suggest EBV-CTL transfer as a promising therapeutic approach for immunocompromised patients with refractory EBV-associated diseases beyond HSCT, as well as patients with preexisting organ dysfunction. TRIAL REGISTRATION Not applicable. FUNDING This study was funded in part by the German Research Foundation (DFG, 158989968/SFB 900), the Deutsche Kinderkrebsstiftung (DKS 2013.09), Wilhelm-Sander-Stiftung (reference 2015.097.1), Ellen-Schmidt-Program of Hannover Medical School, and German Federal Ministry of Education and Research (reference 01EO0802).