Based on the above-mentioned points, since orlistat is safely prescribed for obese people for weight loss, and given the fact that there are previous contradictory results about the mechanism of its molecular effects in the development of colorectal cancer; the present case study was conducted to examines the possible consequences of medication, for the first time, on the expression of OCT4, NANOG, SOX2 and KLF4 genes in cancer. The gene discussed is KLF4; the disease is colorectal cancer.