Characterization of Hormone Receptor and HER2 Status in Breast Cancer Using Mass Spectrometry Imaging.

Immunohistochemical evaluation of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 status stratify the different subtypes of breast cancer and define the treatment course. Triple-negative breast cancer (TNBC), which does not register receptor overexpression, is often associated with worse patient prognosis. Mass spectrometry imaging transcribes the molecular content of tissue specimens without requiring additional tags or preliminary analysis of the samples, being therefore an excellent methodology for an unbiased determination of tissue constituents, in particular tumor markers. In this study, the proteomic content of 1191 human breast cancer samples was characterized by mass spectrometry imaging and the epithelial regions were employed to train and test machine-learning models to characterize the individual receptor status and to classify TNBC. The classification models presented yielded high accuracies for estrogen and progesterone receptors and over 95% accuracy for classification of TNBC. Analysis of the molecular features revealed that vimentin overexpression is associated with TNBC, supported by immunohistochemistry validation, revealing a new potential target for diagnosis and treatment.

mdm2 gene amplification is associated with luminal breast cancer progression in humanized PDX mice and a worse outcome of estrogen receptor positive disease.

Estrogen receptor-positive breast cancer is a highly prevalent but heterogeneous disease among women. Advanced molecular stratification is required to enable individually most efficient treatments based on relevant prognostic and predictive biomarkers. First objective of our study was the hypothesis-driven discovery of biomarkers involved in tumor progression upon xenotransplantation of Luminal breast cancer into humanized mice. The second objective was the marker validation and correlation with the clinical outcome of Luminal breast cancer disease within the GeparTrio trial. An elevated mdm2 gene copy number was associated with enhanced tumor growth and lung metastasis in humanized tumor mice. The viability, proliferation and migration capacity of inherently mdm2 positive breast cancer cells in vitro were significantly reduced upon mdm2 knockdown or anti-mdm2 targeting. An mdm2 gain significantly correlated with a worse DFS and OS of Luminal breast cancer patients, albeit it was also associated with an enhanced preoperative pathological response rate. We provide evidence for an enhanced Luminal breast cancer stratification based on mdm2. Moreover, mdm2 can potentially be utilized as a therapeutic target in the Luminal subtype.

pT3 colorectal cancer revisited: a multicentric study on the histological depth of invasion in more than 1000 pT3 carcinomas-proposal for a new pT3a/pT3b subclassification.

BACKGROUND: Pathological TNM staging (pTNM) is the strongest prognosticator in colorectal carcinoma (CRC) and the foundation of its post-operative clinical management. Tumours that invade pericolic/perirectal adipose tissue generally fall into the pT3 category without further subdivision. METHODS: The histological depth of invasion into the pericolic/perirectal fat was digitally and conventionally measured in a training cohort of 950 CRCs (Munich). We biostatistically calculated the optimal cut-off to stratify pT3 CRCs into novel pT3a (≤3 mm)/pT3b (>3 mm) subgroups, which were then validated in two independent cohorts (447 CRCs, Bayreuth/542 CRCs, Mainz). RESULTS: Compared to pT3a tumours, pT3b CRCs showed significantly worse disease-specific survival, including in pN0 vs pN+ and colonic vs. rectal cancers (DSS: P < 0.001, respectively, pooled analysis of all cohorts). Furthermore, the pT3a/pT3b subclassification remained an independent predictor of survival in multivariate analyses (e.g. DSS: P < 0.001, hazard ratio: 4.41 for pT3b, pooled analysis of all cohorts). While pT2/pT3a CRCs showed similar survival characteristics, pT3b cancers remained a distinct subgroup with dismal survival. DISCUSSION: The delineation of pT3a/pT3b subcategories of CRC based on the histological depth of adipose tissue invasion adds valuable prognostic information to the current pT3 classification and implementation into current staging practices of CRC should be considered.

Comparison of risk assessment in 1652 early ER positive, HER2 negative breast cancer in a real-world data set: classical pathological parameters vs. 12-gene molecular assay (EndoPredict).

BACKGROUND: Risk assessment on the molecular level is important in predictive pathology to determine the risk of metastatic disease for ERpos, HER2neg breast cancer. The gene expression test EndoPredict (EP) was trained and validated for prediction of a 10-year risk of distant recurrence to support therapy decisions regarding endocrine therapy alone or in combination with chemotherapy. The EP test provides the 12-gene Molecular Score (MS) and the EPclin-Score (EPclin), which combines the molecular score with tumor size and nodal status. In this project we investigated the correlation of 12-gene MS and EPclin scores with classical pathological markers. METHODS: EndoPredict-based gene expression profiling was performed prospectively in a total of 1652 patients between 2017 and 2020. We investigated tumor grading and Ki67 cut-offs of 20% for binary classification as well as 10% and 30% for three classes (low, intermediate, high), based on national and international guidelines. RESULTS: 410 (24.8%) of 1652 patients were classified as 12-gene MS low risk and 626 (37.9%) as EPclin low risk. We found significant positive associations between 12-gene MS and grading (p < 0.001), EPclin and grading (p = 0.001), 12-gene MS and Ki67 (p < 0.001), and EPclin and Ki67 (p < 0.001). However, clinically relevant differences between EP test results, Ki67 and tumor grading were observed. For example, 118 (26.3%) of 449 patients with Ki67 > 20% were classified as low risk by EPclin. Same differences were seen comparing EP test results and tumor grading. CONCLUSION: In this study we could show that EP risk scores are distributed differentially among Ki67 expression groups, especially in Ki67 low and high tumors with a substantial proportion of patients with EPclin high risk results in Ki67 low tumors and vice versa. This suggests that classical pathological parameters and gene expression parameters are not interchangeable, but should be used in combination for risk assessment.

Increasing the efficiency of hyperthermic intraperitoneal chemotherapy (HIPEC) by combination with a photosensitive drug in pediatric rhabdomyosarcoma in an animal model.

BACKGROUND: Cytoreductive surgery (CRS) in combination with hyperthermic intraperitoneal chemotherapy (HIPEC) is an option in advanced peritoneal sarcomatosis. Nevertheless, CRS and HIPEC are not successful in all patients. An enhancement of HIPEC using photodynamic therapy (PDT) might be beneficial. Therefore, a combination of the photosensitizer hypericin (HYP) with HIPEC was evaluated in an animal model. PROCEDURE: An established HIPEC animal model for rhabdomyosarcoma (NOD/LtSz-scid IL2Rγnullmice, n = 80) was used. All groups received HYP (100 µg/200 µl) intraperitoneally with and without cisplatin-based (30 or 60 mg/m2 ) HIPEC (37°C or 42°C, for 60 minutes) (five groups, each n = 16). Peritoneal cancer index (PCI) was documented visually and by HYP-based photodynamic diagnosis (PDD). HYP-based PDT of the tumor was performed. Tissue samples were evaluated regarding proliferation (Ki-67) and apoptosis (TUNEL). RESULTS: HYP uptake was detected even in smallest tumor nodes (<1 mm) with improved tumor detection during PDD (PCI with PDD vs. PCI without PDD: 8.5 vs. 7, p < .001***). Apoptotic effects after PDT without HIPEC were limited to the tumor surface, whereas PDT after HIPEC (60 mg/m2 , 42°C) showed additional reduction of tumor proliferation in the top nine to 11 cell layers (50 µm). CONCLUSION: HYP as fluorescent photosensitizer offers an intraoperative diagnostic advantage detecting intraperitoneal tumor dissemination. The combination of HYP and cisplatin-based HIPEC was feasible in vivo, showing enhanced effects on tumor proliferation and apoptosis induction across the tumor surface. Further studies combining HYP and HIPEC will follow to establish a clinical application.

Establishment of a new valid animal model for the evaluation of hyperthermic intraperitoneal chemotherapy (HIPEC) in pediatric rhabdomyosarcoma.

BACKGROUND: Cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy has been established as a novel treatment approach for peritoneal sarcomatosis. Despite promising clinical reports, there is still a lack of knowledge regarding optimal drug usage and local effects. Therefore, we intended to establish a murine animal model for further evaluation. PROCEDURE: Alveolar rhabdomyosarcoma cells were xenotransplanted into NOD/LtSz-scid IL2Rγnullmice (n = 100). The mice received a continuous intraperitoneal lavage with isotonic saline solution as control or with cisplatin (30 or 60 mg/m2 ) as treatment group for 60 minutes at 37°C or 42°C (6 subgroups, each n = 16). Tumor spread was documented by an adapted peritoneal cancer index and MRI (n = 4). Tumor and tissue samples, harvested at the end of the perfusion, were evaluated regarding morphology, proliferation, and apoptosis (H&E-, Ki-67-, cleaved caspase 3-staining, TUNEL assay). RESULTS: Extensive peritoneal sarcomatosis in over 91% of the cases was observed. HIPEC was feasible without acute side effects. Ki-67 staining revealed concentration- or temperature-dependent effects of cisplatin-based HIPEC on the tumors. Although cleaved caspase-3 showed only sporadic apoptotic effects. TUNEL assay detected concentration- or temperature-dependent apoptotic effects at the outer tumor surface. MRI scans confirmed the observed tumor dissemination. CONCLUSION: This is the first animal model for evaluation of HIPEC in pediatric RMS in mice. Cisplatin-based HIPEC had early effects on the proliferation whereas circumscribed apoptotic effects could be detected at the tumor surface. This model allows further insights on the possible efficiency of HIPEC in RMS. Further studies using other drug combinations and treatment will follow.

What turns CREB on? And off? And why does it matter?

Altered expression and function of the transcription factor cyclic AMP response-binding protein (CREB) has been identified to play an important role in cancer and is associated with the overall survival and therapy response of tumor patients. This review focuses on the expression and activation of CREB under physiologic conditions and in tumors of distinct origin as well as the underlying mechanisms of CREB regulation by diverse stimuli and inhibitors. In addition, the clinical relevance of CREB is summarized, including its use as a prognostic and/or predictive marker as well as a therapeutic target.

Tspan8 is expressed in breast cancer and regulates E-cadherin/catenin signalling and metastasis accompanied by increased circulating extracellular vesicles.

Tspan8 exhibits a functional role in many cancer types including pancreatic, colorectal, oesophagus carcinoma, and melanoma. We present a first study on the expression and function of Tspan8 in breast cancer. Tspan8 protein was present in the majority of human primary breast cancer lesions and metastases in the brain, bone, lung, and liver. In a syngeneic rat breast cancer model, Tspan8+ tumours formed multiple liver and spleen metastases, while Tspan8- tumours exhibited a significantly diminished ability to metastasise, indicating a role of Tspan8 in metastases. Addressing the underlying molecular mechanisms, we discovered that Tspan8 can mediate up-regulation of E-cadherin and down-regulation of Twist, p120-catenin, and ß-catenin target genes accompanied by the change of cell phenotype, resembling the mesenchymal-epithelial transition. Furthermore, Tspan8+ cells exhibited enhanced cell-cell adhesion, diminished motility, and decreased sensitivity to irradiation. As a regulator of the content and function of extracellular vesicles (EVs), Tspan8 mediated a several-fold increase in EV number in cell culture and the circulation of tumour-bearing animals. We observed increased protein levels of E-cadherin and p120-catenin in these EVs; furthermore, Tspan8 and p120-catenin were co-immunoprecipitated, indicating that they may interact with each other. Altogether, our findings show the presence of Tspan8 in breast cancer primary lesion and metastases and indicate its role as a regulator of cell behaviour and EV release in breast cancer. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

An Analysis of PIK3CA Hotspot Mutations and Response to Neoadjuvant Therapy in Patients with Breast Cancer from Four Prospective Clinical Trials.

PURPOSE: The PI3K signaling pathway is frequently dysregulated in breast cancer, and mutations in PIK3CA are relevant for therapy resistance in HER2-positive (HER2pos) breast cancer. Mutations in exons 9 or 20 may have different impacts on response to neoadjuvant chemotherapy-based treatment regimens. EXPERIMENTAL DESIGN: We investigated PIK3CA mutations in 1,691 patients with early breast cancer who were randomized into four neoadjuvant multicenter trials: GeparQuattro (NCT00288002), GeparQuinto (NCT00567554), GeparSixto (NCT01426880), and GeparSepto (NCT01583426). The role of different PIK3CA exons and hotspots for pathologic complete response (pCR) following neoadjuvant chemotherapy (NACT) and patient survival were evaluated for distinct molecular subgroups and anti-HER2 treatment procedures. RESULTS: A total of 302 patients (17.9%) of the full cohort of 1,691 patients had a tumor with a PIK3CA mutation, with a different prevalence in molecular subgroups: luminal/HER2-negative (HER2neg) 95 of 404 (23.5%), HER2pos 170 of 819 (20.8%), and triple-negative breast cancer 37 of 468 patients (7.9%). We identified the mutations in PIK3CA exon 20 to be linked with worse response to anti-HER2 treatment (OR = 0.507; 95% confidence interval, 0.320-0.802; P = 0.004), especially in hormone receptor-positive HER2-positive breast cancer (OR = 0.445; 95% confidence interval, 0.237-0.837; P = 0.012). In contrast, exon 9 hotspot mutations p.E452K and p.E545K revealed no noteworthy differences in response therapy. Luminal/HER2neg patients show a trend to have worse treatment response when PIK3CA was mutated. Interestingly, patients with residual disease following neoadjuvant treatment had better survival rates when PIK3CA was mutated. CONCLUSIONS: The PIK3CA hotspot mutation p.H1047R is associated with worse pCR rates following NACT in HER2pos breast cancer, whereas hotspot mutations in exon 9 seem to have less impact.

Nodal lymphangiogenesis and immunophenotypic variations of sinus endothelium in sentinel and non-sentinel lymph nodes of invasive breast carcinoma.

Several studies have demonstrated the de novo formation of lymphatic vessels or the reorganization of lymphatic sinus in tumor-draining lymph nodes, partly preceding the detection of lymphatic metastases. This "lymphovascular niche"is supposed to facilitate the survival of metastatic tumor cells. Few studies on nodal lymphangiogenesis in invasive breast cancer (BC) have been published, not considering tumor-free sentinel lymph nodes (SLN) and tumor types. Specimens of SLN and/ or non-SLN (NSLN) of 95 patients with BC were examined immunohistochemically for expression of the lymphatic endothelial marker D2-40 (podoplanin) on lymphatic vessels and the subcapsular sinus. The number of D2-40-positive lymph vessels in metastases was evaluated with two morphometric methods (Chalkley count and number per HPF). Data was explored with respect to TNM parameters, grading, tumor type, size of metastasis, lymph vessel number and hormone receptor/HER2 status with appropriate statistical tests. Lymphangiogenesis was detected exclusively in and around BC metastases with both methods for lymph vessel quantification being equivalent. Lymph vessel number correlated with the size of metastases, being significantly higher in larger metastases (p < 0.001). There was no significant statistical difference with respect to tumor types. Intranodal lymphangiogenesis could not be verified by D2-40 staining in any of the tumor-free lymph nodes examined. However, D2-40 was frequently detected in sinus endothelial/virgultar cells of the subcapsular sinus, partly with strong uniform positivity. Staining intensity and stained proportion of the subcapsular sinus were markedly heterogeneous, significantly correlating with each other both in SLN and NSLN (p < 0.001). A higher proportion of D2-40 stained subcapsular sinus in SLN was significantly associated with worse overall survival (p = 0.0036) and an independent prognostic parameter in multivariate analysis (p = 0.033, HR 2.87). Further studies are necessary to elucidate the biological and clinical significance of the observed immunophenotypic variations of nodal sinus endothelium.

[Clinically relevant molecular pathological diagnostics in breast cancer]. / Klinisch relevante molekularpathologische Diagnostik beim Mammakarzinom.

In breast cancer, the current guideline for pathological workup includes recommendations for advanced molecular analysis of certain predictive molecular markers in addition to basic immunohistochemical diagnostics. These markers are determined depending on tumor stage, including sequencing techniques and immunohistochemical methods. This comprises the systematic investigation of molecular alterations such as PIK3CA or BRCA1,2 mutations, NTRK fusions, or microsatellite instability as a basis for targeted therapy. Further alterations, for example in the PI3K pathway, ESR1 alterations, or ERBB2 mutations, may also be relevant for individual therapy decisions especially in the context of resistant or relapsed disease. Thus, particularly in advanced stages, a more comprehensive molecular characterization of the tumor may reveal genetic alterations that act as tumor drivers and provide targets for personalized therapies. Due to the large number of potential molecular targets, NGS panel diagnostics are a suitable approach in this conjunction with immunohistochemical characterization and the individual clinical situation. Molecular based therapeutical strategies outside of entity-specific approvals should be discussed in an interdisciplinary team within the framework of a molecular tumor board.

High expression of insulinoma-associated protein 1 (INSM1) distinguishes colorectal mixed and pure neuroendocrine carcinomas from conventional adenocarcinomas with diffuse expression of synaptophysin.

Complementary to synaptophysin and chromogranin A, insulinoma-associated protein 1 (INSM1) has emerged as a sensitive marker for the diagnosis of neuroendocrine neoplasms. Since there are no comparative data regarding INSM1 expression in conventional colorectal adenocarcinomas (CRCs) and colorectal mixed adenoneuroendocrine carcinomas/neuroendocrine carcinomas (MANECs/NECs), we examined INSM1 in a large cohort of conventional CRCs and MANECs/NECs. In conventional CRC, we put a special focus on conventional CRC with diffuse expression of synaptophysin, which carry the risk of being misinterpreted as a MANEC or a NEC. We investigated INSM1 according to the immunoreactive score in our main cohort of 1,033 conventional CRCs and 21 MANECs/NECs in comparison to the expression of synaptophysin and chromogranin A and correlated the results with clinicopathological parameters and patient survival. All MANECs/NECs expressed INSM1, usually showing high or moderate expression (57% high, 34% moderate, and 9% low), which distinguished them from conventional CRCs, which were usually INSM1 negative or low, even if they diffusely expressed synaptophysin. High expression of INSM1 was not observed in conventional CRCs. Chromogranin A was negative/low in most conventional CRCs (99%), but also in most MANECs/NECs (66%). Comparable results were observed in our independent validation cohorts of conventional CRC (n = 274) and MANEC/NEC (n = 19). Similar to synaptophysin, INSM1 expression had no prognostic relevance in conventional CRCs, while true MANEC/NEC showed a highly impaired survival in univariate and multivariate analyses (e.g. disease-specific survival: p < 0.001). MANECs/NECs are a highly aggressive variant of colorectal cancer, which must be reliably identified. High expression of INSM1 distinguishes MANEC/NEC from conventional CRCs with diffuse expression of the standard neuroendocrine marker synaptophysin, which do not share the same dismal prognosis. Therefore, high INSM1 expression is a highly specific/sensitive marker that is supportive for the diagnosis of true colorectal MANEC/NEC.

LRP1B-a prognostic marker in tubo-ovarian high-grade serous carcinoma.

Low-density lipoprotein (LDL) receptor-related protein 1B (LRP1B) is a member of the LDL receptor family and has often been discussed as a tumor suppressor gene, as its down-regulation is correlated with a poor prognosis in multiple carcinoma entities. Due to the high metastasis rate into the fatty peritoneal cavity and current research findings showing a dysregulation of lipid metabolism in tubo-ovarian high-grade serous carcinoma (HGSC), we questioned the prognostic impact of the LRP1B protein expression. We examined a well-characterized large cohort of 571 patients with primary HGSC and analyzed the LRP1B protein expression via immunohistochemical staining (both in tumor and stroma cells separately), performed precise bioimage analysis with QuPath, and calculated the prognostic impact using SPSS. Our results demonstrate that LRP1B functions as a significant prognostic marker for overall survival (OS) and progression-free survival (PFS) in HGSC on the protein level. High cytoplasmic expression of LRP1B in tumor, stroma, and combined tumor and stroma cells has a significantly positive association with a mean prolongation of the OS by 42 months (P = .005), 29 months (P = .005), and 25 months (P = .001), respectively. Additionally, the mean PFS was 18 months longer in tumor (P = .002), 19 months in stroma (P = .004), and 19 months in both cell types combined (P = .01). Our results remained significant in multivariate analysis. We envision LRP1B as a potential prognostic tool that could help us understand the functional role of lipid metabolism in advanced HGSC, especially regarding liposomal medications.

High EVI1 and PARP1 expression as favourable prognostic markers in high-grade serous ovarian carcinoma.

BACKGROUND: Mechanisms of development and progression of high-grade serous ovarian cancer (HGSOC) are poorly understood. EVI1 and PARP1, part of TGF-ß pathway, are upregulated in cancers with DNA repair deficiencies with DNA repair deficiencies and may influce disease progression and survival. Therefore we questioned the prognostic significance of protein expression of EVI1 alone and in combination with PARP1 and analyzed them in a cohort of patients with HGSOC. METHODS: For 562 HGSOC patients, we evaluated EVI1 and PARP1 expression by immunohistochemical staining on tissue microarrays with QuPath digital semi-automatic positive cell detection. RESULTS: High EVI1 expressing (> 30% positive tumor cells) HGSOC were associated with improved progression-free survival (PFS) (HR = 0.66, 95% CI: 0.504-0.852, p = 0.002) and overall survival (OS) (HR = 0.45, 95% CI: 0.352-0.563, p < 0.001), including multivariate analysis. Most interestingly, mutual high expression of both proteins identifies a group with particularly good prognosis. Our findings were proven technically and clinically using bioinformatical data sets for single-cell sequencing, copy number variation and gene as well as protein expression. CONCLUSIONS: EVI1 and PARP1 are robust prognostic biomarkers for favorable prognosis in HGSOC and imply further research with respect to their reciprocity.

Increased expression of IDO1 is associated with improved survival and increased number of TILs in patients with high-grade serous ovarian cancer.

BACKGROUND: The enzyme indoleamine 2,3-dioxygenase 1 (IDO1) plays a crucial role in regulating the immune system's response to tumors, but its exact role in cancer, especially in high-grade serous ovarian cancer (HGSOC), remains controversial. We aimed to investigate the prognostic impact of IDO1 expression and its correlation with tumor-infiltrating lymphocytes (TILs) in HGSOC. METHODS: Immunohistochemical (IHC) staining and bioimage analysis using the QuPath software were employed to assess IDO1 protein expression in a well-characterized cohort of 507 patients with primary HGSOC. Statistical evaluation was performed using SPSS, and in silico validation considering IDO1 mRNA expression in bulk and single-cell gene expression datasets was conducted. Additionally, IDO1 expression in interferon-gamma (IFNG) stimulated HGSOC cell lines was analyzed. RESULTS: Our findings revealed that IDO1 protein and mRNA expression serve as positive prognostic markers for overall survival (OS) and progression-free survival (PFS) in HGSOC. High IDO1 expression was associated with a significant improvement in OS by 21 months (p < 0.001) and PFS by 6 months (p = 0.016). Notably, elevated IDO1 expression correlated with an increased number of CD3+ (p < 0.001), CD4+ (p < 0.001), and CD8+ TILs (p < 0.001). Furthermore, high IDO1 mRNA expression and protein level were found to be associated with enhanced responsiveness to pro-inflammatory cytokines, particularly IFNG. CONCLUSIONS: Our study provides evidence that IDO1 expression serves as a positive prognostic marker in HGSOC and is associated with an increased number of CD3+, CD4+ and CD8+ TILs. Understanding the intricate relationship between IDO1, TILs, and the tumor microenvironment may hold the key to improving outcomes in HGSOC.

Multiparametric Phenotyping of Circulating Tumor Cells for Analysis of Therapeutic Targets, Oncogenic Signaling Pathways and DNA Repair Markers.

Detection of circulating tumor cells (CTCs) has been established as an independent prognostic marker in solid cancer. Multiparametric phenotyping of CTCs could expand the area of application for this liquid biomarker. We evaluated the Amnis® brand ImageStream®X MkII (ISX) (Luminex, Austin, TX, USA) imaging flow cytometer for its suitability for protein expression analysis and monitoring of treatment effects in CTCs. This was carried out using blood samples from patients with head and neck squamous cell carcinoma (n = 16) and breast cancer (n = 8). A protocol for negative enrichment and staining of CTCs was established, allowing quantitative analysis of the therapeutic targets PD-L1 and phosphorylated EGFR (phospho-EGFR), and the treatment response marker γH2AX as an indicator of radiation-induced DNA damage. Spiking experiments revealed a sensitivity of 73% and a specificity of 100% at a cut-off value of ≥3 CTCs, and thus confirmed the suitability of the ISX-based protocol to detect phospho-EGFR and γH2AX foci in CTCs. Analysis of PD-L1/-L2 in both spiked and patient blood samples further showed that assessment of heterogeneity in protein expression within the CTC population was possible. Further validation of the diagnostic potential of this ISX protocol for multiparametric CTC analysis in larger clinical cohorts is warranted.

Polycomb Protein BMI-1 as a Potential Therapeutic Target in Mucinous Ovarian Cancer.

BACKGROUND/AIM: Mucinous ovarian carcinoma (mOC) is a rare subtype with distinct clinical characteristics and biological behavior that differentiate them from other epithelial ovarian cancers. This study aimed to evaluate BMI-1 expression as a potential target for therapeutic approaches in advanced stage mOC. MATERIALS AND METHODS: We performed gene set, as well as transcription factor enrichment analysis and immunohistochemistry assessing of the BMI-1 protein levels in tissue specimens of eighteen mucinous ovarian cancer patients. To validate the clinical relevance of the findings, we performed cell viability assays and western blot analysis utilizing high-grade serous (HGSC) and mOC cell lines. RESULTS: BMI1 expression was not significantly associated with patient age, FIGO stage, lymph node status, and family history. With regard to progression-free survival, there was also no significant association (p=0.418). Cell viability was significant decreased in response to carboplatin in HGSC cells TYK-nu and OVHASO, and in mOC cell lines COV644 and EFO-27. Western blot analysis demonstrated various expression levels across all cell lines. CONCLUSION: BMI-1 could be a useful potential therapeutic target in some ovarian cancer patients, including mOC patients.

How VEGF-A and its splice variants affect breast cancer development - clinical implications.

BACKGROUND: Altered expression levels and structural variations in the vascular endothelial growth factor (VEGF) have been found to play important roles in cancer development and to be associated with the overall survival and therapy response of cancer patients. Particularly VEGF-A and its splice variants have been found to affect physiological and pathological angiogenic processes, including tumor angiogenesis, correlating with tumor progression, mostly caused by overexpression. This review focuses on the expression and impact of VEGF-A splice variants under physiologic conditions and in tumors and, in particular, the distribution and role of isoform VEGF165b in breast cancer. CONCLUSIONS AND PERSPECTIVES: Many publications already highlighted the importance of VEGF-A and its splice variants in tumor therapy, especially in breast cancer, which are summarized in this review. Furthermore, we were able to demonstrate that cytoplasmatic VEGFA/165b expression is higher in invasive breast cancer tumor cells than in normal tissues or stroma. These examples show that the detection of VEGF splice variants can be performed also on the protein level in formalin fixed tissues. Although no quantitative conclusions can be drawn, these results may be the starting point for further studies at a quantitative level, which can be a major step towards the design of targeted antibody-based (breast) cancer therapies.

Homologous Recombination Deficiency as an Ovarian Cancer Biomarker in a Real-World Cohort: Validation of Decentralized Genomic Profiling.

The diagnostic evaluation of homologous recombination deficiency (HRD) is central to define targeted therapy strategies for patients with ovarian carcinoma. We evaluated HRD in 514 ovarian carcinoma samples by next-generation sequencing of DNA libraries, including BRCA1/BRCA2 and 26,523 single-nucleotide polymorphisms using the standardized Myriad HRD assay, with the predefined cut point of ≥42 for a positive genomic instability score (GIS). All samples were measured in the central Myriad laboratory and in an academic molecular pathology laboratory. A positive GIS was detected in 196 (38.1%) of tumors, whereas 318 (61.9%) were GIS negative. Combining GIS and BRCA mutations, a total of 200 (38.9%) of the 514 tumors were HRD positive. A positive GIS was significantly associated with high-grade serous histology (P < 0.000001), grade 3 tumors (P = 0.001), and patient age <60 years (P = 0.0003). The concordance between both laboratories for the GIS status was 96.9% (P < 0.000001), with a sensitivity of 94.6% and a specificity of 98.4%. Concordance for HRD status was 97.1% (499 of 514 tumors). The percentage of HRD-positive tumors in our real-life cohort was similar to the proportion observed in the recently published PAOLA-1 trial, with high concordance between central and local laboratories. Our results support introduction of the standardized HRD assay in academic molecular pathology laboratories, thus broadening access to personalized oncology strategies for patients with ovarian cancer worldwide.

Hotspot ESR1 Mutations Are Multimodal and Contextual Modulators of Breast Cancer Metastasis.

Constitutively active estrogen receptor α (ER/ESR1) mutations have been identified in approximately one-third of ER+ metastatic breast cancers. Although these mutations are known as mediators of endocrine resistance, their potential role in promoting metastatic disease has not yet been mechanistically addressed. In this study, we show the presence of ESR1 mutations exclusively in distant but not local recurrences in five independent breast cancer cohorts. In concordance with transcriptomic profiling of ESR1-mutant tumors, genome-edited ESR1 Y537S and D538G-mutant cell models exhibited a reprogrammed cell adhesive gene network via alterations in desmosome/gap junction genes and the TIMP3/MMP axis, which functionally conferred enhanced cell-cell contacts while decreasing cell-extracellular matrix adhesion. In vivo studies showed ESR1-mutant cells were associated with larger multicellular circulating tumor cell (CTC) clusters with increased compactness compared with ESR1 wild-type CTCs. These preclinical findings translated to clinical observations, where CTC clusters were enriched in patients with ESR1-mutated metastatic breast cancer. Conversely, context-dependent migratory phenotypes revealed cotargeting of Wnt and ER as a vulnerability in a D538G cell model. Mechanistically, mutant ESR1 exhibited noncanonical regulation of several metastatic pathways, including secondary transcriptional regulation and de novo FOXA1-driven chromatin remodeling. Collectively, these data provide evidence for ESR1 mutation-modulated metastasis and suggest future therapeutic strategies for targeting ESR1-mutant breast cancer. SIGNIFICANCE: Context- and allele-dependent transcriptome and cistrome reprogramming in mutant ESR1 cell models elicit diverse metastatic phenotypes related to cell adhesion and migration, which can be pharmacologically targeted in metastatic breast cancer.