The family of protein kinases includes many oncogenes and growth factor 
receptors, many of which have been linked to the pathogenesis and progression of 
cancer. Protein tyrosine kinases such as HER-2/c-erbB-2 and the epidermal growth 
factor receptor (EGFR) have been linked specifically to breast cancer, and 
perturbations of HER-2 affect response to chemotherapy. We have reviewed the 
biology of protein kinases in human breast cancer, as well as their 
translational applications to breast cancer patients. We have studied the 
spectrum of protein kinases expressed in human breast cancer cells and have 
identified four protein kinases with potentially important functions in breast 
cancer: rak (src-related), TK5 (which we now designate JAK3), the focal adhesion 
kinase (FAK), and STK1 (human M015/CAK). We describe the potential significance 
of these genes in breast cancer, as well as our methodology for identifying and 
characterizing novel genes in breast cancer.