Exploratory study of clonality determined by expression of tumor markers in intrinsic subtypes of breast cancers.

Abstract #5060 [Background] However expression profile-based intrinsic subtypes revealed heterogeneity of breast cancer, several biological issues are not clarified yet, especially in tumor development. [Objectives] In order to clarify the relationship between intrinsic subtypes and positivity of tumor markers (TMs), CEA, CA15-3, BCA225 and NCC-ST439 were measured from sera taken from patients at the relapse retrospectively. In addition to the analysis of positivity of TMs, migration of TMs were analyzed in each intrinsic subtype, especially focused on changes of CA15-3 (equivalent to soluble MUC1) to identify the heterogeneity and development to other subtypes in the meaning of TMs expression. [Methods] Sera were collected from seventy five patients of newly diagnosed metastatic breast cancer. Intrinsic subtypes were simply determined by immunohistochemical staining as Luminal A (LA) ,B (LB), HER2 and TN. The positivity of TM was defined if it elevated 20% higher than normal upper limit. [Results] The positive rate of any TMs were higher in order of LA, LB, HER2 and TN. There was significant difference between Luminal (LA+LB) and TN in positive rate of TMs(p Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5060.