Interestingly, the expression of CD133 as a cancer stem cell maker is also known to be upregulated both dependently and independently on HIF signaling; although CD133-positive cells were found in the tumor hypoxic regions of colon and rectal cancers, CD133 expression is inversely correlated to HIF-1A expression in patients who received preoperative chemotherapy. This evidence concerns the gene PROM1 and neoplasm.