👤 Jan H N Lindeman

Inflammatory breast cancer (IBC) is a rare and clinically distinct form of breast cancer associated with poor outcomes. The biological mechanisms driving IBC remain poorly understood, partly due to limited large-scale genomic studies that directly compare IBC with non-IBC cases. We conducted a retrospective analysis of 140 patients with IBC (68 primary tumors and 72 metastatic tumors) and 2,317 patients with non-IBC (700 primary tumors, 65 local recurrences, and 1,552 metastases). We compared clinicopathologic features, single-nucleotide variants, copy-number variants, tumor mutational burden, and exploratory survival outcomes between IBC and non-IBC tumors. The most frequent somatic alterations in IBC were detected in TP53 (72%), ERBB2 (32%), PIK3CA (24%), CCND1 (12%), MYC (9%), FGFR1 (8%), and GATA3 (8%). Multivariate logistic regression revealed a significant enrichment of TP53 single-nucleotide variants in IBC, particularly in HER2+ and hormone receptor-positive disease. Tumor mutational burden did not differ between IBC and non-IBC cases. In HER2+ disease, a pathway analysis revealed an enrichment of NOTCH pathway alterations. TP53, CCND1, and RB1 alterations were associated with poor outcomes in IBC. This study provides a comprehensive resource of somatic alterations in a large cohort of patients with metastatic IBC and non-IBC, highlighting genomic features associated with worse outcomes. Our findings reveal a significant enrichment of TP53 mutations, reinforcing its critical role in IBC pathogenesis. Few other distinct differences in IBC were observed, suggesting further investigations-beyond bulk sequencing of the somatic genome-are required to better understand the biology driving this aggressive disease. Show less

Subareolar sclerosing ductal hyperplasia (SSDH) is a distinct type of complex sclerosing hyperplastic lesion first described by Rosen in 1987. There have been rare studies investigating SSDH; however, no genetic study has been performed to date. Seven SSDH cases, diagnosed between 2013 and 2024, were identified. All were subjected to next-generation sequencing (523 genes). Patient ages ranged from 40 to 74 years (median = 46). All lesions were located in the subareolar region. Each showed the characteristic appearance of the lesion, as described in the seminal study, with usual ductal hyperplasia in a densely sclerotic background imparting an 'infiltrative' appearance. None of the cases showed atypical hyperplasia or carcinoma. DNA sequencing identified PI3K pathway alterations in all seven cases: PIK3CA (n = three, one with two alterations), PIK3R1 (n = three) and PIK3C3 (n = one, with concurrent FAT1 mutation). SSDH shows PI3K pathway alterations similar to those seen in other non-atypical and atypical proliferative lesions as well as benign and malignant neoplasms of the breast. This finding may explain the rare association of SSDH with atypical hyperplasia, in-situ and invasive carcinoma. Show less

Inflammatory breast cancer (IBC) is a rare and poorly characterized type of breast cancer with an aggressive clinical presentation. The biological mechanisms driving the IBC phenotype are relatively undefined-partially due to a lack of comprehensive, large-scale genomic studies and limited clinical cohorts. A retrospective analysis of 2457 patients with metastatic breast cancer who underwent targeted tumor-only DNA-sequencing was performed at Dana-Farber Cancer Institute. Clinicopathologic, single nucleotide variant (SNV), copy number variant (CNV) and tumor mutational burden (TMB) comparisons were made between clinically confirmed IBC cases within a dedicated IBC center versus non-IBC cases. Clinicopathologic differences between IBC and non-IBC cases were consistent with prior reports-including IBC being associated with younger age at diagnosis, higher grade, and enrichment with hormone receptor (HR)-negative and HER2-positive tumors. The most frequent somatic alterations in IBC involved Taken together, this study provides a comprehensive, clinically informed landscape of somatic alterations in a large cohort of patients with IBC. Our data support higher frequency of Show less

Breast cancer is a heterogeneous disease that comprises multiple histological and molecular subtypes. To gain insight into mutations that drive breast tumorigenesis, we describe a pipeline for the identification and validation of tumor suppressor genes. Based on an in vivo genome-wide CRISPR/Cas9 screen in Trp53 Show less

Previous studies indicate a role for Oncostatin M (OSM) in atherosclerosis and other chronic inflammatory diseases for which inhibitory antibodies are in development. However, to date no intervention studies with OSM have been performed, and its relation to coronary heart disease (CHD) has not been studied. Gene expression analysis on human normal arteries (n = 10) and late stage/advanced carotid atherosclerotic arteries (n = 127) and in situ hybridization on early human plaques (n = 9) showed that OSM, and its receptors, OSM receptor (OSMR) and Leukemia Inhibitory Factor Receptor (LIFR) are expressed in normal arteries and atherosclerotic plaques. Chronic OSM administration in APOE*3Leiden.CETP mice (n = 15/group) increased plasma E-selectin levels and monocyte adhesion to the activated endothelium independently of cholesterol but reduced the amount of inflammatory Ly-6CHigh monocytes and atherosclerotic lesion size and severity. Using aptamer-based proteomics profiling assays high circulating OSM levels were shown to correlate with post incident CHD survival probability in the AGES-Reykjavik study (n = 5457). Chronic OSM administration in APOE*3Leiden.CETP mice reduced atherosclerosis development. In line, higher serum OSM levels were correlated with improved post incident CHD survival probability in patients, suggesting a protective cardiovascular effect. Show less

Clinical decision making in abdominal aortic aneurysms (AAA) relies completely on diameter. At this point, improved decision tools remain an unmet medical need. Our goal was to identify changes at the molecular level specifically leading up to AAA rupture. Aortic wall tissue specimens were collected during open elective (eAAA; n=31) or emergency repair of ruptured AAA (rAAA; n=17), and gene expression was investigated using microarrays. Identified candidate genes were validated with quantitative real-time polymerase chain reaction in an independent sample set (eAAA: n=46; rAAA: n=18). Two gene sets were identified, 1 set containing 5 genes linked to terminal progression, that is, positively associated with progression of larger AAA, and with rupture ( Our study shows a specific molecular fingerprint for terminal AAA disease. These changes appear to converge at activation of HIF-1α signaling in mesenchymal cells. Aspects of this cascade might represent targets for rupture risk assessment. Show less

Key augmented processes in atherosclerosis have been identified, whereas less is known about downregulated pathways. Here, we applied a systems biology approach to examine suppressed molecular signatures, with the hypothesis that they may provide insight into mechanisms contributing to plaque stability. Muscle contraction, muscle development, and actin cytoskeleton were the most downregulated pathways (false discovery rate=6.99e-21, 1.66e-6, 2.54e-10, respectively) in microarrays from human carotid plaques (n=177) versus healthy arteries (n=15). In addition to typical smooth muscle cell (SMC) markers, these pathways also encompassed cytoskeleton-related genes previously not associated with atherosclerosis. SYNPO2, SYNM, LMOD1, PDLIM7, and PLN expression positively correlated to typical SMC markers in plaques (Pearson r>0.6, P<0.0001) and in rat intimal hyperplasia (r>0.8, P<0.0001). By immunohistochemistry, the proteins were expressed in SMCs in normal vessels, but largely absent in human plaques and intimal hyperplasia. Subcellularly, most proteins localized to the cytoskeleton in cultured SMCs and were regulated by active enhancer histone modification H3K27ac by chromatin immunoprecipitation-sequencing. Functionally, the genes were downregulated by PDGFB (platelet-derived growth factor beta) and IFNg (interferron gamma), exposure to shear flow stress, and oxLDL (oxidized low-density lipoprotein) loading. Genetic variants in PDLIM7, PLN, and SYNPO2 loci associated with progression of carotid intima-media thickness in high-risk subjects without symptoms of cardiovascular disease (n=3378). By eQTL (expression quantitative trait locus), rs11746443 also associated with PDLIM7 expression in plaques. Mechanistically, silencing of PDLIM7 in vitro led to downregulation of SMC markers and disruption of the actin cytoskeleton, decreased cell spreading, and increased proliferation. We identified a panel of genes that reflect the altered phenotype of SMCs in vascular disease and could be early sensitive markers of SMC dedifferentiation. Show less