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Introduction/Background* The vascular endothelial growth factor (VEGF) plays an import role in emergence and spread of high-grade serous tubo-ovarian carcinoma (HGSTOC). Bevacizumab, a monoclonal antibody targeting VEGFA, has therefore been added to first-line treatment of advanced HGSTOC. We here map the dynamics of different stromal components of the tumour microenvironment under chemotherapy with or without bevacizumab. Methodology We performed single-cell RNA-sequencing on 62,461 cells sampled from 6 HGSTOC patients before and after neo-adjuvant platin-based chemotherapy with or without bevacizumab. We identified 44 stromal cell subclusters on which we applied Mixed-effects modelling of Associations of Single Cells to identify cell populations associated with bevacizumab exposure and pathological response using the chemotherapeutic response score. Result(s)* Our study revealed diverse stromal cell subsets associated with bevacizumab exposure. The addition of bevacizumab to frontline chemotherapy increased the odds of endothelial cell (ECs) prevalence by a 3-fold (OR 2.91, 95%CI:2.36-3.58; p Conclusion* We here provide initial evidence on the mechanisms underlying early response to bevacizumab and frontline chemotherapy in HGSTOC, including tip cell impairment, reduced hypoxia and a decrease in regulatory T cells. However, bevacizumab exposure increased the influx of PDGFC-expressing macrophages capable to bypass VEGFA-dependent angiogenesis.

Objective We assessed the curative effect of a second curettage in patients with persistent hCG serum levels after first curettage for a gestational trophoblastic disease (GTD). Study Design This prospective observational study used the data of the Belgian register for GTD between July 2012 and January 2017. We analysed the data of patients who underwent a second curettage. We included 313 patients in the database. Primary endpoints were need for second curettage and chemotherapy. Results Thirty-seven patients of the study population (12 %) underwent a second curettage. 20 had persistent human chorionic gonadotropin hormone (hCG) elevation before second curettage. Of them, 9 patients (45 %) needed no further treatment afterwards. Eleven patients (55 %) needed further chemotherapy. Nine (82 %) were cured with single-agent chemotherapy and 2 patients (18 %) needed multi-agent chemotherapy. Of the 37 patients, patients with hCG levels below 5000 IU/L undergoing a second curettage were cured without chemotherapy in 65 % versus 45 % of patients with hCG level more than 5000 IU/L. Of the ten patients with a hCG level below 1000 IU/L, eight were cured without chemotherapy. Conclusions Patients with post-mole gestational trophoblastic neoplasia can benefit from a second curettage to avoid chemotherapy, especially when the hCG level is lower than 5000 IU/L.

OBJECTIVES: To apply the Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) to a consecutive series of endometrial cancer (EC) patients diagnosed at a tertiary referral center and assign EC specimens to one of four molecular subgroups using immunohistochemistry (IHC) for p53/mismatch repair protein expression and sequencing for Polymerase Epsilon Exonuclease Domain Mutations (POLE-EDM). Mismatch Repair Deficient (MMR-D) cases were more thoroughly investigated to identify underlying somatic or germline genetic defects. METHODS: Hundred-and eight consecutive endometrial cancer patients, diagnosed between March 2017 and April 2019, were subjected to immunohistochemical and molecular analysis, according to ProMisE. IHC for p53 and the mismatch repair proteins (MLH1, PMS2, MSH6 and PMS2) was performed. All patients were also tested for POLE-EDM by Sanger sequencing. In addition, tumor and corresponding normal tissue of cases with abnormal MMR IHC were tested by PCR for microsatellite instability (MSI) (MSI analysis system, Promega). Hypermethylation of MLH1 promotor was tested with (methylation specific) multiplex ligation dependent probe amplification. MMR-D cases were subjected to germline mutation analysis of the mismatch repair genes, using next generation sequencing on MiSeq (Illumina) with the BRCA Hereditary Cancer MASTR Plus, (Multiplicom/Agilent), RNA mutation analysis and MLPA. RESULTS: FIGO classification was stage IA (n = 54), IB (n = 22) II(n = 8), III(n = 18) and IV(n = 6). Of the 33 patients with MMR-D on IHC (31%), 26 showed MLH1 promotor hypermethylation as the probable cause of MMR-D. The remaining 7 patients without MLH1 promotor hypermethylation were referred for germline analysis of Lynch syndrome. Six patients carried a pathogenic germline mutation in one of the mismatch repair genes: MSH6(n = 3), PMS2(n = 1), MLH1(n = 1) and MSH2 (n = 1). Pathogenic POLE-EDM were identified in 7 (6%) patients. Multiple molecular features (POLE-EDM + MMR-D or POLE-EDM + p53 abnormal) were observed in 4 patients (4%). A high concordance between MMR-D and microsatellite instability was observed in our cohort. In cases of a genetic defect in the MMR genes, we do note a large proportion of cases exhibiting microsatellite instability. On the contrary a hypermutation state, as seen in POLE EDM, does not result in accompanied phenotypic changes in MSI status. CONCLUSION: The ProMisE classification proved to be an efficient and easily implementable system. Future research should elucidate the precise biological and prognostic meaning of the cases with multiple molecular markers. ispartof: GYNECOLOGIC ONCOLOGY vol:157 issue:1 pages:245-251 ispartof: location:United States status: published