Invasive lobular carcinoma (ILC) is the second most common subtype of breast cancer following invasive ductal carcinoma (IDC) and characterized by the loss of E-cadherin-mediated adherens junctions. Despite displaying unique histologic and clinical features, ILC still remains a chronically understudied disease, with limited knowledge gleaned from available laboratory research models. Here we report a comprehensive 2D and 3D phenotypic characterization of four estrogen receptor-positive human ILC cell lines: MDA-MB-134, SUM44, MDA-MB-330, and BCK4. Compared with the IDC cell lines MCF7, T47D, and MDA-MB-231, ultra-low attachment culture conditions revealed remarkable anchorage independence unique to ILC cells, a feature not evident in soft-agar gels. Three-dimensional Collagen I and Matrigel culture indicated a generally loose morphology for ILC cell lines, which exhibited differing preferences for adhesion to extracellular matrix proteins in 2D. Furthermore, ILC cells were limited in their ability to migrate and invade in wound-scratch and transwell assays, with the exception of haptotaxis to Collagen I. Transcriptional comparison of these cell lines confirmed the decreased cell proliferation and E-cadherin-mediated intercellular junctions in ILC while uncovering the induction of novel pathways related to cyclic nucleotide phosphodiesterase activity, ion channels, drug metabolism, and alternative cell adhesion molecules such as N-cadherin, some of which were differentially regulated in ILC versus IDC tumors. Altogether, these studies provide an invaluable resource for the breast cancer research community and facilitate further functional discoveries toward understanding ILC, identifying novel drug targets, and ultimately improving the outcome of patients with ILC. These findings provide the breast cancer research community with a comprehensive assessment of human invasive lobular carcinoma (ILC) cell line signaling and behavior in various culture conditions, aiding future endeavors to develop therapies and to ultimately improve survival in patients with ILC. .

INTRODUCTION: Low-grade dysplasia (LGD) is the best predictor of neoplastic progression in Barrett's esophagus (BE). Most LGD cases are downstaged to nondysplastic (ND) BE on expert pathologist review, which is prone to interobserver variation and not widely available. Recent studies indicate that a risk prediction assay (TissueCypher) risk stratifies patients with NDBE for neoplastic progression. We aimed to investigate whether this risk prediction assay predicts neoplastic progression in BE patients with LGD. METHODS: A blinded, retrospective cohort study was derived from the screening cohort of a randomized controlled trial of SURveillance vs RadioFrequency ablation for BE patients with LGD. Hematoxylin and eosin and p53 immunohistochemistry slides from the first endoscopy with LGD were independently reviewed by 3 expert pathologists and tested by the risk prediction assay. Revision diagnoses of NDBE were considered low risk, although indefinite for dysplasia, and LGD were considered high risk for progression. RESULTS: A total of 155 BE patients (123 men), mean age 61 ± 10 years, were analyzed. Thirty-four patients (22%) progressed to high-grade dysplasia/esophageal adenocarcinoma (median time 2.4 years) and 121 did not progress (median high-grade dysplasia/esophageal adenocarcinoma-free surveillance 7.9 years). The risk prediction assay sensitivity was 68% vs 76% for the 3 pathologists, and specificity was 79% vs 64%–77.0% for the pathologists. The assay detected 50%–56% of progressors that were downstaged to NDBE by the pathologists. DISCUSSION: The risk prediction assay provided significant risk stratification in BE patients with LGD and identified progressors that the experts downstaged to NDBE. This objective assay provides an effective solution to the lack of standardization of expert pathology review of LGD.