**5. Clinical studies**

There have been an increasing number of clinical trials done on solid tumors using retinoids. However, our search of trials listed www.clinicaltrials.gov does not show any trials on CRCs using retinoids, Tretinoin or Liarozole. There were several trials listed for breast, lung, prostate, pancreatic, renal, cervical, brain, skin, and several hematologic malignancies. Given the pre-clinical data discussed above, it seems like it would be reasonable to develop a retinoid-based trial for CRC.
