CD9 and colorectal cancer: High expression (more than 90% of positive cells) was detected for several CD markers (e.g., CD 326 (EpCAM, one of the first cancer-associated antigens identified [19]), CD164 (promising new target for diagnosis and treatment of colon cancer [18]), CD147 (a potential 5-FU resistance biomarker for colorectal cancer patient [20]), CD98 (a potential prognostic biomarker for colorectal carcinoma [21]), CD29 (cell surface marker associated with cancer self-renewal [22]), CD26 (reported as a marker for colorectal cancer stem cells [23]) and CD9 to name a few) was detected.