{'fraction_non_alphanumeric': 0.042801556420233464, 'fraction_numerical': 0.033073929961089495, 'mean_word_length': 5.233333333333333, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Abstract PD7-05: Correlation ofCDH1alterations and aberrant E-cadherin expression in lobular carcinomas

Background: E-cadherin (ECAD), encoded by the CDH1 gene, is expressed in the majority of invasive ductal carcinomas (IDC). In contrast, ECAD expression is lost in ˜90% of invasive lobular carcinomas (ILC) due to genomic alterations of CDH1. Immunohistochemical (IHC) staining for ECAD has thus increasingly been utilized to differentiate between ductal and lobular lesions. This study examines the correlation between CDH1 mutation profile, morphology and ECAD IHC status in invasive breast carcinomas (BC). Methods: The Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) platform is a hybrid capture next-generation sequencing assay to detect somatic alterations in exons and selected introns of 468 cancer-related genes. Invasive BC tested from 1/2014 – 5/2018 which yielded a CDH1 alteration were identified and only cases with ECAD IHC results were included. Histologic features were extracted from pathology reports. All available HE 48/209) with CDH1 alteration still exhibits ECAD expression. Morphologically this subset consists of ILC in 60% (29/48), IMC in 25% (12/48) and IDC in 15% (7/48). Our preliminary findings suggest that aberrant ECAD expression can occur in BC with morphologic features of ILC due to certain CDH1 alterations that most likely result in non-functional ECAD complex. BC with histologic features of ILC should therefore not be re-classified as IDC/IMC based solely on the status of ECAD expression. Given that ILC is clinically distinct from IDC, correct classification based on morphological and molecular features is prudent. Citation Format: Grabenstetter A, Mohanty AS, DeLair DF, Tan LK, Ross DS. Correlation of CDH1 alterations and aberrant E-cadherin expression in lobular carcinomas [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD7-05.