Preclinical data suggest that different solid tumors could respond to mTOR inhibitors and report on enhanced antitumor activity in combination with different traditional cytostatic drugs. Furthermore recent preclinical data suggest that mTOR inhibition may induce tumor reduction in colon cancer xenographs. Temsirolimus (CCI-779) has been widely investigated in different clinical settings and is presently registered for treatment of renal cell carcinomas. Furthermore, is has recently shown response in metastatic breast cancer patients, but at present there are no clinical data on efficacy or safety in metastatic colorectal cancer patients.