NGF and cancer: In addition to its role in the development and maintenance of neuronal cells, recent studies have shown that NGF and its receptors are found and sometimes even overexpressed outside the nervous system, where it may promote cancer cell proliferation, growth, and invasion in several types of cancer such as breast, pancreas, and prostate cancer (Pflug et al, 1995; Walch and Marchetti, 1999; Sakamoto et al, 2001a, 2001b; Schneider et al, 2001; Zhu et al, 2001, 2002; Kishibe et al, 2002; Davidson et al, 2003; Dolle et al, 2003).