The recent development of multi-gene assays for gene expression profiling has contributed significantly to the understanding of the clinically and biologically heterogeneous breast cancer (BC) disease. PAM50 is one of these assays used to stratify BC patients and individualize treatment. The present study was conducted to characterize PAM50-based intrinsic subtypes among Ethiopian BC patients.Formalin-fixed paraffin-embedded tissues were collected from 334 BC patients who attended five different Ethiopian health facilities. All samples were assessed using the PAM50 algorithm for intrinsic subtyping.The tumor samples were classified into PAM50 intrinsic subtypes as follows: 104 samples (31.1%) were luminal A, 91 samples (27.2%) were luminal B, 62 samples (18.6%) were HER2-enriched and 77 samples (23.1%) were basal-like. The intrinsic subtypes were found to be associated with clinical and histopathological parameters such as steroid hormone receptor status, HER2 status, Ki-67 proliferation index and tumor differentiation, but not with age, tumor size or histological type. An immunohistochemistry-based classification of tumors (IHC groups) was found to correlate with intrinsic subtypes.The distribution of the intrinsic subtypes confirms previous immunohistochemistry-based studies from Ethiopia showing potentially endocrine-sensitive tumors in more than half of the patients. Health workers in primary or secondary level health care facilities can be trained to offer endocrine therapy to improve breast cancer care. Additionally, the findings indicate that PAM50-based classification offers a robust method for the molecular classification of tumors in the Ethiopian context.
Abstract Brustkrebs: Über zwei Jahrzehnte untersuchten klinische Forscher bei erkrankten Frauen die beiden Invasionsmarker uPA und PAI‐I. Die Langzeitstudien erlauben eine bessere Risikoabschätzung und individuellere Behandlungen der Patientinnen
Abstract Introduction. Neoadjuvant chemotherapy (NACT) is the standard of care in aggressive breast cancer, including triple negative breast cancer (TNBC). Cytotoxic drugs specifically target proliferating cells, however, patient outcome is variable. Tumor physiology and response to therapy are orchestrated by an intricate interplay between cancer, stromal and immune cells collectively forming the tumor microenvironment. We have recently uncovered a feedback mechanism of tumor cells and fibroblasts, involving IFNB1 signaling, that supports tumor cells in the recovery from chemotherapy-induced stress. Here, we wanted to assess whether targets of IFNB1 signaling in fibroblasts and tumor cells would qualify as predictive markers of pathological complete response (pCR) after neoadjuvant therapy (NACT) as prognostic markers for the course of the disease. Methods and Patients. RNA-sequencing data from in vitro experiments found the GO-term GO:0051607 ‘defense response to virus’ significantly enriched. Twentyfour genes intersected between differentially expressed genes and the genes of this GO-term. We selected three of the encoded proteins a) interferon induced with helicase C domain 1 IFIH1, b) interferon alpha-inducible protein ISG15, c) 2'-5'-oligoadenylate synthetase OAS1 to test their expression in human specimens of TNBCs after NACT by immunohistochemistry (IHC). None of the respective genes correlated with recurrence free survival when tested in treatment-naïve tumor biopsies (KM Plotter). A prospective consecutively enrolled cohort (2000 - 2021) was available with an overall pCR rate of 46%. pCR was defined by no invasive cancer cell in breast or axilla (ypT0 N0). The median follow-up for iDFS was 36.2 months (6-154) and for OS 39.3 months (6-214).Primary objective was the correlation between IFIH1, ISG15 and OAS1 protein expression in the residual tumor by non-pCR or in the tumor bed by pCR. Second objective was the association of IFIH1, ISG15 and OAS1 protein expression to invasive disease-free survival (iDFS) and overall survival (OS). Results. To date, IHC staining has been established for IFIH1, ISG15 and OAS1. In representative stainings of FFPE tissue samples with pCR we did not detect any positive signal for IFIH1 and ISG15 in stromal cells like fibroblast or lymphocytes. Slight to strong protein expression was detected by non-pCR in cancer cells, stromal cells and tumour infiltrating lymphocytes. In contrast OAS1 was expressed especially strong in lymphocytes by pCR or non-pCR. Cancer cell showed moderate OAS1 expression. IHC analysis and of the entire cohort is in progress including the analyses of the association of these markers to pCR, non-pCR and iDFS/OS. Conclusion. Using samples from our consecutive, multicentre enrolled cohort, an association between the expression of markers of an IFNB1-triggered antiviral response and pCR and survival was demonstrated in patients of the TNBC subgroup. Analysis of the entire cohort is necessary to potentially demonstrate applicability of an interferon-response as predictor of survival. Citation Format: Marcus Bauer, Martina Vetter, Ana Maia, Efstathios Vlachavas, Brigitta Michels, Mireia Berdiel-Acer, Kathleen Schüler, Alessandra Morselli, Manio Skarlatou, Christoph Thomssen, Stefan Wiemann. Communication between tumor cells and fibroblasts as a prognostic factor of NACT in TNBC [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-08-15.
The aim was to evaluate the accuracy of BI-RADS categories 3 - 5 in breast ultrasound (US) as the first-line imaging method.5077 examinations of a consecutive, unselected and mixed collective of symptomatic and asymptomatic patients were performed. Of these examinations, 835 cases of BIRADS 3 - 5 could be analyzed.The PPV with respect to a malignant lesion for BI-RADS 3, 4, 5 was 0.03, 0.48, and 0.97, respectively. When BI-RADS 4 and 5 cases are considered to be suspicious, the ratio of benign to malignant findings corresponds to 1:1.8. Analyzing BIRADS 3 - 5 lesions, the sensitivity, specificity and accuracy are 0.92, 0.85, and 0.87, respectively.The data support the feasibility of US for discriminating malignant from benign findings corresponding to the ACR BI-RADS classification without excessively increasing the number of unnecessary biopsies.
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Abstract GRB2 is an adaptor protein of HER2 (and several other tyrosine kinases), which we identified as a novel BECN1 (Beclin 1) interacting partner. GRB2 co-immunoprecipitated with BECN1 in several breast cancer cell lines and regulates autophagy through a mechanism involving the modulation of the class III PI3Kinase VPS34 activity. In ovo studies in a CAM (Chicken Chorioallantoic Membrane) model indicated that GRB2 knockdown, as well as overexpression of GRB2 loss-of-function mutants (Y52A and S86A-R88A) compromised tumor growth. These differences in tumor growth correlated with differential autophagy activity, indicating that autophagy effects might be related to the effects on tumorigenesis. Our data highlight a novel function of GRB2 as a BECN1 binding protein and a regulator of autophagy.
In breast cancer, the promising efficacy of farnesyltransferase inhibitors (FTIs) in preclinical studies is in contrast to only limited effects in clinical Phase II-III trials. The objective of this study was to explore the clinical relevance of farnesyltransferase β-subunit (FNTB) single nucleotide promoter polymorphisms (FNTB-173 6G > 5G (rs3215788), -609 G > C (rs11623866) and -179 T > A (rs192403314)) in early breast cancer. FNTB genotyping was performed by pyrosequencing in 797 patients from a prospective multicentre observational PiA trial (NCT01592825). In the total cohort, the FNTB-173 6G > 5G polymorphism was an independent predictor of RFI (HR = 0.568; 95% CI = 0.339-0.949, p = 0.031), OS (HR = 0.629; 95% CI = 0.403-0.980, p = 0.040) and BCSS (HR = 0.433; 95% CI = 0.213-0.882; p = 0.021), whereas the FNTB-609 G > C polymorphism was an independent predictor of RFI (HR = 0.453; 95% CI = 0.226-0.910, p = 0.026) and BCSS (HR = 0.227; 95% CI = 0.075-0.687, p = 0.009). Subtype analysis revealed the independent prognostic relevance of FNTB promoter polymorphisms, particularly in TNBC but not in luminal or HER2-positive intrinsic subtypes. Finally, we used electrophoretic mobility shift assays (EMSAs) to confirm in vitro that the polymorphism FNTB-173 6G > 5G resulted in the differential binding of nuclear proteins from five different breast cancer cell lines. This is the first study on breast cancer suggesting that FNTB promoter polymorphisms (i) are independent prognostic biomarkers, particularly in patients with early TNBC, and (ii) could modulate FNTB's transcriptional activity.
The tumor-suppressive let-7 microRNA family targets various oncogene-encoding mRNAs. We identify the let-7 targets HMGA2, LIN28B and IGF2BP1 to form a let-7 antagonizing self-promoting oncogenic triangle. Surprisingly, 3′-end processing of IGF2BP1 mRNAs is unaltered in aggressive cancers and tumor-derived cells although IGF2BP1 synthesis was proposed to escape let-7 attack by APA-dependent (alternative polyadenylation) 3′ UTR shortening. However, the expression of the triangle factors is inversely correlated with let-7 levels and promoted by LIN28B impairing let-7 biogenesis. Moreover, IGF2BP1 enhances the expression of all triangle factors by recruiting the respective mRNAs in mRNPs lacking AGO proteins and let-7 miRNAs. This indicates that the downregulation of let-7, largely facilitated by LIN28B upregulation, and the protection of let-7 target mRNAs by IGF2BP1-directed shielding in mRNPs synergize in enhancing the expression of triangle factors. The oncogenic potential of this triangle was confirmed in ovarian cancer (OC)-derived ES-2 cells transduced with let-7 targeting decoys. In these, the depletion of HMGA2 only diminishes tumor cell growth under permissive conditions. The depletion of LIN28B and more prominently IGF2BP1 severely impairs tumor cell viability, self-renewal and 2D as well as 3D migration. In conclusion, this suggests the targeting of the HMGA2-LIN28B-IGF2BP1 triangle as a promising strategy in cancer treatment.
