These studies have provided strong evidence to show that β2-M acts similarly to a prototypical oncogenic factor capable of stimulating growth and progression of various types of cancers, including breast cancer (17), prostate cancer (18), lung cancer (19), gastrointestinal (20), nasopharyngeal cancers (21), multiple myeloma (22), and particularly, lymphocytic malignancies (23), such as non-Hodgkin's lymphoma and multiple myeloma. This evidence concerns the gene B2M and breast cancer.