Abstract: This document provides methods and materials related to assessing and treating breast cancer patients. For example, methods and materials that involve assessing a breast cancer patient to determine whether the patient has (1) cancer cells that over express HER-2 polypeptides or comprise a HER-2 amplification and (2) at least an intermediate CYP2D6 metabolizer status are provided.

Abstract: This document provides methods and materials involved in assessing the risk of developing breast cancer in patients with atypical hyperplasia. For example, methods and materials for using the level of Ki67 expression (e.g., percent Ki67+cells or Ki67 staining intensity) to determine if a patient with atypical hyperplasia has an increased risk of developing breast cancer within an early phase from diagnosis (e.g., within ten years of biopsy) or an increased risk of developing breast cancer at a late phase from diagnosis (e.g., at a point more than ten years of biopsy) are provided.

Abstract: Methods for determining risk of developing breast cancer are described.