GAPDH and cancer: On this basis and since the GAPDH is commonly used as housekeeping gene, also in studies using bisphosphonates, and since it is upregulated in many cancer (7–9,11) and downregulated by chemotherapic drugs (6), we assessed the effects, if any, of some bisphosphonates commonly used in cancer bone disease on GAPH gene expression in breast and prostate cancer cell lines.