Strengthening health data on a rare and heterogeneous disease: sarcoma incidence and histological subtypes in Germany

Background: The population-based incidence of sarcoma and its histological subtypes in Germany is unknown. Up-to-date information on a disease with an incidence comparable to other cancer entities is of high public health relevance. The aim of this study was to determine this incidence and to detect significant changes in incidence trends using data from German epidemiological cancer registries. Methods: Pooled data from the German Centre for Cancer Registry Data with a primary diagnosis occurring in 2013 were used. To date, this is the latest data on cancer incidence available for Germany. All German cancer registries with sufficient completeness were included (10 out of 11), covering a population of 70.0 million people, representing 87% of the German population. All malignant sarcomas according to the RARECARE Project and the WHO classification 2002 were considered for analysis and, above all, gastrointestinal stromal tumours (GIST) of uncertain behaviour. Sensitivity analysis was performed excluding certain histologies. Results: The analysis included 3404 cases in men and 3442 cases in women diagnosed in 2013. The age adjusted sarcoma incidence (European standard) was 7.4 (men) and 6.6 (women) per 100,000 inhabitants. About 70% of sarcomas were soft tissue sarcomas, about 22% GIST, and about 9% bone sarcomas. The most common histological subtypes besides GIST were fibrosarcomas (14%) and liposarcomas (12%) in men and complex mixed and stromal neoplasms (22%), non-uterine leiomysarcomas (10%) and fibrosarcomas (9%) in women. Considering the trend for the years of diagnosis 2004 to 2013, there was a significant increase in incidence for GIST while the incidence of soft tissue sarcomas (only men) as well as of bone sarcoma stayed constant over time. As to soft tissue sarcoma in women, the incidence stayed constant up to the year 2009 and significantly decreased afterwards. Conclusion: This study is the first detailed analysis of a German-wide population-based sarcoma incidence showing results comparable to the incidence detected in the RARECARE Project

qPCR in gastrointestinal stromal tumors: Evaluation of reference genes and expression analysis of KIT and the alternative receptor tyrosine kinases FLT3, CSF1-R, PDGFRB, MET and AXL

<p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumors (GIST) represent the most common mesenchymal tumors of the gastrointestinal tract. About 85% carry an activating mutation in the <it>KIT </it>or <it>PDGFRA </it>gene. Approximately 10% of GIST are so-called wild type GIST (wt-GIST) without mutations in the hot spots. In the present study we evaluated appropriate reference genes for the expression analysis of formalin-fixed, paraffin-embedded and fresh frozen samples from gastrointestinal stromal tumors. We evaluated the gene expression of <it>KIT </it>as well as of the alternative receptor tyrosine kinase genes <it>FLT3</it>, <it>CSF1-R</it>, <it>PDGFRB</it>, <it>AXL </it>and <it>MET </it>by qPCR. wt-GIST were compared to samples with mutations in <it>KIT </it>exon 9 and 11 and <it>PDGFRA </it>exon 18 in order to evaluate whether overexpression of these alternative RTK might contribute to the pathogenesis of wt-GIST.</p> <p>Results</p> <p>Gene expression variability of the pooled cDNA samples is much lower than the single reverse transcription cDNA synthesis. By combining the lowest variability values of fixed and fresh tissue, the genes <it>POLR2A</it>, <it>PPIA</it>, <it>RPLPO </it>and <it>TFRC </it>were chosen for further analysis of the GIST samples. Overexpression of <it>KIT </it>compared to the corresponding normal tissue was detected in each GIST subgroup except in GIST with <it>PDGFRA </it>exon 18 mutation. Comparing our sample groups, no significant differences in the gene expression levels of <it>FLT3</it>, <it>CSF1R </it>and <it>AXL </it>were determined. An exception was the sample group with <it>KIT </it>exon 9 mutation. A significantly reduced expression of <it>CSF1R</it>, <it>FLT3 </it>and <it>PDGFRB </it>compared to the normal tissue was detected. GIST with mutations in <it>KIT </it>exon 9 and 11 and in <it>PDGFRA </it>exon 18 showed a significant <it>PDGFRB </it>downregulation.</p> <p>Conclusions</p> <p>As the variability of expression levels for the reference genes is very high comparing fresh frozen and formalin-fixed tissue there is a strong need for validation in each tissue type. None of the alternative receptor tyrosine kinases analyzed is associated with the pathogenesis of wild-type or mutated GIST. It remains to be clarified whether an autocrine or paracrine mechanism by overexpression of receptor tyrosine kinase ligands is responsible for the tumorigenesis of wt-GIST.</p

Fibrinogen-like protein 2 in gastrointestinal stromal tumour

Gastrointestinal stromal tumour (GIST), the most common sarcoma of the gastrointestinal tract, can be treated effectively with tyrosine kinase inhibitors, such as imatinib. Cancer immune therapy has limited efficacy, and little is known about the immune suppressive factors in GISTs. Fibrinogen-like protein 2 (FGL2) is expressed either as a membrane-associated protein or as a secreted soluble protein that has immune suppressive functions. We found that GISTs expressed FGL2 mRNA highly compared to other types of cancer in a large human cancer transcriptome database. GIST expressed FGL2 frequently also when studied using immunohistochemistry in two large clinical series, where 333 (78%) out of the 425 GISTs were FGL2 positive. The interstitial cells of Cajal, from which GISTs may originate, expressed FGL2. FGL2 expression was associated with small GIST size, low mitotic counts and low tumour-infiltrating lymphocyte (TIL) counts. Patients whose GIST expressed FGL2 had better recurrence-free survival than patients whose GIST lacked expression. Imatinib upregulated FGL2 in GIST cell lines, and the patients with FGL2-negative GIST appeared to benefit most from long duration of adjuvant imatinib. We conclude that GISTs express FGL2 frequently and that FGL2 expression is associated with low TIL counts and favourable survival outcomes.Peer reviewe

Expression of cell cycle regulators and frequency of TP53 mutations in high risk gastrointestinal stromal tumors prior to adjuvant imatinib treatment

Despite of multitude investigations no reliable prognostic immunohistochemical biomarkers in GIST have been established so far with added value to predict the recurrence risk of high risk GIST besides mitotic count, primary location and size. In this study, we analyzed the prognostic relevance of eight cell cycle and apoptosis modulators and of TP53 mutations for prognosis in GIST with high risk of recurrence prior to adjuvant treatment with imatinib. In total, 400 patients with high risk for GIST recurrence were randomly assigned for adjuvant imatinib either for one or for three years following laparotomy. 320 primary tumor samples with available tumor tissue were immunohistochemically analyzed prior to treatment for the expression of cell cycle regulators and apoptosis modulators cyclin D1, p21, p16, CDK4, E2F1, MDM2, p53 and p-RB1. TP53 mutational analysis was possible in 245 cases. A high expression of CDK4 was observed in 32.8% of all cases and was associated with a favorable recurrence free survival (RFS), whereas high expression of MDM2 (12.2%) or p53 (35.3%) was associated with a shorter RFS. These results were independent from the primary KIT or PDGFRA mutation. In GISTs with higher mitotic counts was a significantly increased expression of cyclin D1, p53 and E2F1. The expression of p16 and E2F1 significantly correlated to a non-gastric localization. Furthermore, we observed a significant higher expression of p21 and E2F1 in KIT mutant GISTs compared to PDGFRA mutant and wt GISTs. The overall frequency of TP53 mutations was low (n = 8; 3.5%) and could not be predicted by the immunohistochemical expression of p53. In summary, mutation analysis in TP53 plays a minor role in the subgroup of high-risk GIST before adjuvant treatment with imatinib. Strong expression of MDM2 and p53 correlated with a shorter recurrence free survival, whereas a strong expression of CDK4 correlated to a better recurrence free survival.Peer reviewe

Pitfalls in mutational testing and reporting of common KIT and PDGFRA mutations in gastrointestinal stromal tumors

<p>Abstract</p> <p>Background</p> <p>Mutation analysis of <it>KIT </it>and <it>PDGFRA </it>genes in gastrointestinal stromal tumors is gaining increasing importance for prognosis of GISTs and for prediction of treatment response. Several groups have identified specific mutational subtypes in <it>KIT </it>exon 11 associated with an increased risk of metastatic disease whereas GISTs with <it>PDGFRA </it>mutations often behave less aggressive. Furthermore, in advanced GIST disease with proven <it>KIT </it>exon 9 mutation the doubled daily dose of 800 mg imatinib increases the progression free survival and is now recommended both in the European and the American Guidelines. In Germany, there are still no general rules how to perform mutational analysis.</p> <p>Methods</p> <p>When comparing results from six different molecular laboratories we recognized the need of standardisation. Six German university laboratories with experience in mutation analysis in GISTs joined together to develop recommendations for the mutation analysis of the most common and clinically relevant hot spots, i. e. <it>KIT </it>exons 9 and 11 and <it>PDGFRA </it>exon 18. We performed a three-phased interlaboratory trial to identify pitfalls in performing molecular analysis in GISTs.</p> <p>Results</p> <p>We developed a design for a continuous external laboratory trial. In 2009 this external trial was conducted by 19 laboratories via the initiative for quality assurance in pathology (QuiP) of the German Society of Pathology and the Professional Association of German Pathologists.</p> <p>Conclusions</p> <p>By performing a three-phased internal interlaboratory trial and conducting an external trial in Germany we were able to identify potential pitfalls when performing KIT and PDGFRA mutational analysis in gastrointestinal stromal tumors. We developed standard operation procedures which are provided with the manuscript to allow other laboratories to prevent these pitfalls.</p

Risk Factors for Gastrointestinal Stromal Tumor Recurrence in Patients Treated With Adjuvant Imatinib

Peer reviewe

Selective inactivation of hypomethylating agents by SAMHD1 provides a rationale for therapeutic stratification in AML.

Hypomethylating agents decitabine and azacytidine are regarded as interchangeable in the treatment of acute myeloid leukemia (AML). However, their mechanisms of action remain incompletely understood, and predictive biomarkers for HMA efficacy are lacking. Here, we show that the bioactive metabolite decitabine triphosphate, but not azacytidine triphosphate, functions as activator and substrate of the triphosphohydrolase SAMHD1 and is subject to SAMHD1-mediated inactivation. Retrospective immunohistochemical analysis of bone marrow specimens from AML patients at diagnosis revealed that SAMHD1 expression in leukemic cells inversely correlates with clinical response to decitabine, but not to azacytidine. SAMHD1 ablation increases the antileukemic activity of decitabine in AML cell lines, primary leukemic blasts, and xenograft models. AML cells acquire resistance to decitabine partly by SAMHD1 up-regulation. Together, our data suggest that SAMHD1 is a biomarker for the stratified use of hypomethylating agents in AML patients and a potential target for the treatment of decitabine-resistant leukemia

Potential Targets' Analysis Reveals Dual PI3K/mTOR Pathway Inhibition as a Promising Therapeutic Strategy for Uterine Leiomyosarcomas-an ENITEC Group Initiative

Purpose: Uterine sarcomas are rare and heterogeneous tumors characterized by an aggressive clinical behavior. Their high rates of recurrence and mortality point to the urgent need for novel targeted therapies and alternative treatment strategies. However, no molecular prognostic or predictive biomarkers are available so far to guide choice and modality of treatment. Experimental Design: We investigated the expression of several druggable targets (phospho-S6(S240) ribosomal protein, PTEN, PDGFR-alpha, ERBB2, and EGFR) in a large cohort of human uterine sarcoma samples (288), including leiomyosarcomas, low-grade and high-grade endometrial stromal sarcomas, undifferentiated uterine sarcomas, and adenosarcomas, together with 15 smooth muscle tumors of uncertain malignant potential (STUMP), 52 benign uterine stromal tumors, and 41 normal uterine tissues. The potential therapeutic value of the most promising target, p-S6(S240), was tested in patient-derived xenograft (PDX) leiomyosarcoma models. Results: In uterine sarcomas and STUMPs, S6S240 phosphorylation (reflecting mTOR pathway activation) was associated with higher grade (P = 0.001) and recurrence (P = 0.019), as shown by logistic regression. In addition, p-S6(S240) correlated with shorter progression-free survival (P = 0.034). Treatment with a dual PI3K/mTOR inhibitor significantly reduced tumor growth in 4 of 5 leiomyosarcoma PDX models (with tumor shrinkage in 2 models). Remarkably, the 4 responding models showed basal p-S6(S240) expression, whereas the nonresponding model was scored as negative, suggesting a role for p-S6(S240) in response prediction to PI3K/mTOR inhibition. Conclusions: Dual PI3K/mTOR inhibition represents an effective therapeutic strategy in uterine leiomyosarcoma, and p-S6(S240) expression is a potential predictive biomarker for response to treatment. (C)2017 AACR.Peer reviewe

SLUG transcription factor : a pro-survival and prognostic factor in gastrointestinal stromal tumour

Background: The SLUG transcription factor has been linked with the KIT signalling pathway that is important for gastrointestinal stromal tumour (GIST) tumourigenesis. Its clinical significance in GIST is unknown. Methods: Influence of SLUG expression on cell proliferation and viability were investigated in GIST48 and GIST882 cell lines. The association between tumour SLUG expression in immunohistochemistry and recurrence-free survival (RFS) was studied in two clinical GIST series, one with 187 patients treated with surgery alone, and another one with 313 patients treated with surgery and adjuvant imatinib. Results: SLUG downregulation inhibited cell proliferation, induced cell death in both cell lines, and sensitised GIST882 cells to lower imatinib concentrations. SLUG was expressed in 125 (25.0%) of the 500 clinical GISTs evaluated, and expression was associated with several factors linked with unfavourable prognosis. SLUG expression was associated with unfavourable RFS both when patients were treated with surgery alone (HR = 3.40, 95% CI = 1.67-6.89, P = 0.001) and when treated with surgery plus adjuvant imatinib (HR = 1.83, 95% CI = 1.29-2.60, P = 0.001). Conclusions: GIST patients with high tumour SLUG expression have unfavourable RFS. SLUG may mediate pro-survival signalling in GISTs.Peer reviewe

Predictive and prognostic factors associated with soft tissue sarcoma response to chemotherapy: a subgroup analysis of the European Organisation for Research and Treatment of Cancer 62012 study

Background: The European Organization for Research and Treatment of Cancer (EORTC) 62012 study was a Phase III trial of doxorubicin versus doxorubicin–ifosfamide chemotherapy in 455 patients with advanced soft tissue sarcoma (STS). Analysis of the main study showed that combination chemotherapy improved tumor response and progression-free survival, but differences in overall survival (OS) were not statistically significant. We analyzed factors prognostic for tumor response and OS, and assessed histological subgroup and tumor grade as predictive factors to identify patients more likely to benefit from combination chemotherapy. Methods: Central pathology review was performed by six reference pathologists. Gender, age, performance status, time from first presentation with sarcoma to starting palliative chemotherapy, tumor grade, histological subgroup, primary tumor site involvement, and sites of metastases were assessed as prognostic factors. Results: Three hundred and ten patients were included in this study. Discordance between local and central pathology opinion of tumor histology and tumor grade was observed in 98 (32%) and 122 (39%) cases, respectively. In multivariate analysis, liposarcoma patients had improved tumor response compared to other histological subgroups, whilst patients with metastases other than lung, liver or bone had a poorer response [odds ratio (OR) 0.42, 95% confidence interval (CI) 0.23–0.78; p = 0.006]. Patients with bone metastases had reduced OS [hazard ratio (HR) 1.56, 95% CI 1.16–2.09; p = 0.003]. By central pathology review, patients with undifferentiated pleomorphic sarcoma (UPS) had improved tumor response and OS with doxorubicin–ifosfamide compared to single-agent doxorubicin (OR 9.90, 95% CI 1.93–50.7 and HR 0.44, 95% CI 0.26–0.79, respectively). Grade III tumors had improved response with combination chemotherapy but there was no interaction between chemotherapy and grade on OS. Conclusions: Prospective central pathology review of tumor histology should be integrated into future STS clinical trials. Doxorubicin–ifosfamide may be most appropriate for young, fit patients with poorly differentiated Grade III tumors including UPS