Background: Defining the molecular profile (gene and protein expression) of normal breast tissue is essential to identifying markers for cellular subtypes in the normal human breast. These markers could serve as biomarkers for prevention trials or represent new therapeutic targets if they are also expressed in early breast cancers. The gene and protein expression in normal breast tissue may be dependent on the stage of the menstrual cycle, whether the woman is pre- or post-menopausal, prior pregnancy and breast feeding history, and age. The molecular profile of metastatic breast tumors may differ from that of the primary tumor and differ in metastases from different anatomic sites. Identification of genes/proteins unique to these lesions may help identify the processes responsible for metastatic spread at a molecular level and lead to the development of new molecularly targeted drugs. Similarly, isolation and characterization of breast cancer stem cells could provide new approaches for the treatment and prevention of breast cancer.

Objectives: To define the molecular profile of normal breast tissue from pre- and post-menopausal women of varying age and parity (nulliparous to multiparous) and in different phases of the menstrual cycle; to study the molecular profile of primary and metastatic breast cancer lesions; and to identify and characterize breast cancer stem cells and establish cell lines from the pleural fluid of women with breast cancer and malignant pleural effusions.

Eligibility: Women who are undergoing cosmetic breast surgery that entails resection of a portion of the breast (e.g., reduction mammoplasty) and who do not have a history of breast cancer; women with known or suspected breast cancer who are having a primary tumor biopsied or resected or having a metastatic lesion biopsied or resected; or women with breast cancer who are undergoing pleurocentesis for a suspected or known malignant pleural effusion.

Design: Normal breast tissues from cosmetic breast procedures that are performed in women without a history of breast cancer at Suburban Hospital will be snap frozen in liquid nitrogen and sent to the NCI for storage and analysis. Demographic information will be collected from the women undergoing the procedure. Similarly, a portion of biopsies obtained from primary or metastatic lesions in women with suspected or known breast cancer at Suburban Hospital or the NIH will be collected after materials are obtained for diagnostic purposes, snap frozen in liquid nitrogen, and sent to the NCI with demographic information. The unneeded fluid from pleurocenteses performed in women with breast cancer and malignant pleural effusions will be transported (unfrozen) to an NCI lab for immediate processing (FAC sorting to isolate breast cancer stem cells). RNA will be extracted from tissues and cDNA microarrays will be used to study gene expression. Proteomic analysis of normal and malignant breast tissue will be studied using reverse-phase tissue lysates.