PC-cell derived growth factor (PCDGF), also known as granulin precursor or progranulin, is the largest member of a family of growth modulators characterized by a unique cysteine-rich motif. Biological and pathological studies point out to the importance of this growth factor in breast cancer and other human cancers, where it stimulates proliferation and survival, and promotes metastasis. These studies suggest that PCDGF is a suitable therapeutic and diagnostic target for the development of novel cancer therapy and diagnosis. (C) 2003 Elsevier Inc. All rights reserved.