The etiology of breast cancer is a complex interplay of various factors, including genetic alterations. A number of studies have been made to identify and characterize mutations that frequently occur during breast tumorigenesis. In this paper, we have described a new deletion, located on the long arm of chromosome 7. Patients whose tumor carried a deletion on chromosome 7q had a significantly shorter survival time. These findings identify the long arm of chromosome 7 as a candidate region for a putative tumor (or metastasis) suppressor gene.