Abstract PD2-11: Ki-67 (30-9) scoring and differentiation in Luminal A and Luminal B breast cancer subtypes

摘要: Introduction Ki-67 labeling index is a powerful prognostic marker in breast cancer (BC). It especially useful assessing the risk of recurrence for estrogen receptor-positive (ER+) BC, where it may be considered surrogate molecular assays distinguishing Luminal A-like from B-like BCs. We evaluated performance VENTANA anti (30-9) rabbit monoclonal antibody distant relapses large series patients with ER+ BC treated and followed up single Institution. Patients Methods The initial cohort (9415 patients) comprised all women operated on early ER+, HER2-negative (HER2-) at European Institute Oncology (IEO), who did not receive neo-adjuvant treatment1. subsequently restricted to 3986 between 1998-2002 whom long-term follow-up data was available. A case-cohort built by randomly selecting 17% above (679 patients, including 84 events). Additional 303 developed an event (metastasis organs or death due as primary events) were added this cohort. using anti-Ki-67 (Ventana Medical Systems, Inc., Tucson, AZ) OptiView IHC DAB detection BenchMark ULTRA advanced staining platform. stained slides scoring method described International Working Group. “Luminal A-like” tumors that HER2-, main outcome disease-free survival (DDFS) calculated date surgery any first last contact patient. Cumulative incidence curves drawn sub-cohort differences subtypes assessed log-rank test. Multivariable Cox regression inverse sampling probability weighting used evaluate metastasis across groups. Results In sub-cohort, 400 (58.9%) had “luminal 279 (41.1%) B-like” BC. 10-year cumulative (or related event) two groups respectively 8.2% 24.5% (log rank P whole case-cohort, multivariable analysis confirmed statistically significant increased events B-Like” compared A-Like “BC (HR=1.97; 95% CI 1.38-2.79), after adjustment pT, pN, PVI menopausal status. Conclusion anti-Ki67 antibody, able stratify endocrine responsive maximizing number those classified having 9Luminal A-like9 intrinsic subtype use cytotoxic drugs could avoided. Funding source: Ventana Inc. References Maisonneuve P, Disalvatore D, Rotmensz N, et al. (2014) Proposed new clinicopathological definitions luminal B (HER2-negative) subtypes.Breast Cancer Res16:R65 Citation Format: Viale G, Hanlon Newell AE, Walker E, Bai I, Russo L, Dell9Orto P. differentiation [abstract]. In: Proceedings 2018 San Antonio Breast Symposium; Dec 4-8; Antonio, TX. Philadelphia (PA): AACR; Res 2019;79(4 Suppl):Abstract nr PD2-11.