Clinicopathological Characteristics of a Distinct Tumor Phenotype: Invasive Lobular Carcinoma With Tubular Elements in the West German Study Group ADAPTcycle Trial
Martin Radner , Sandy Burmeister , Katarzyna Jóźwiak , Nora Schaumann , Malte Gronewold , Mieke Raap , Stephan Bartels , Henriette Christgen , Leonie D. Kandt , Pia Hillmann , Ulrich Lehmann , Oleg Gluz , Monika Graeser , Sherko Kümmel , Christine zu Eulenburg , Nadia Harbeck , Hans Kreipe , Matthias Christgen
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引用次数: 0
Abstract
Invasive lobular carcinoma with tubular elements (ILC-TE) is a recently identified variant of invasive lobular breast carcinoma (ILC). The histology of ILC-TE is defined by noncohesive carcinoma cells mixed with cohesive tubular elements and complete loss of epithelial (E)-cadherin. Cell–cell adhesion is partially restored by switching from an E-cadherin–deficient to a placental (P)-cadherin–proficient status (EPS). The prevalence of ILC-TE remains unknown. Here, we report data from the central pathology review of >4500 hormone receptor–positive/HER2-negative breast cancer (BC) cases recruited to the West German Study Group (WSG) ADAPTcycle trial (NCT04055493). The central pathology review included prospective assessment of BC types, variants, and E-cadherin expression. Cases classified as ILC-TE were analyzed for their molecular features and clinicopathological characteristics. Pure ILC with complete loss of E-cadherin accounted for 630 of 4619 (13.6%) BC cases. ILC-TE accounted for 47 of 630 (7.5%) lobular carcinomas, making it more than twice as prevalent as mixed BC (NST/ILC). ILC-TE harbored deleterious CDH1/E-cadherin mutations in 27 of 35 (77%) cases tested. EPS was detected in 43 of 47 (91%) ILC-TE cases. EPS was significantly more common in ILC-TE than in classic ILC or other ILC variants (P < .001). Clinically, ILC-TE was associated with cT1 stage (P = .023), cN0 status (P = .024), lower histologic grade (P = .004), and lower Ki67 (P = .012). In contrast, solid ILC was associated with higher Ki67 (P = .006). Following preoperative endocrine therapy, higher post–preoperative endocrine therapy Ki67 levels were observed in trabecular ILC, solid-papillary ILC, and pleomorphic ILC (P < .001, P = .006, and P = .021, respectively). In summary, ILC-TE is a quite common ILC variant that is associated with EPS, less-aggressive clinical features, and slow growth.
期刊介绍:
Laboratory Investigation is an international journal owned by the United States and Canadian Academy of Pathology. Laboratory Investigation offers prompt publication of high-quality original research in all biomedical disciplines relating to the understanding of human disease and the application of new methods to the diagnosis of disease. Both human and experimental studies are welcome.