To determine if the anti-tumor effect of anti-sMCAM mAb treatment was dependent on MCAM expression by the tumor cells themselves or by the host, we treated immunodeficient NSG mice bearing either human DLD1 (mMCAM-positive) or LoVo (mMCAM-negative) CRC tumors with anti-sMCAM mAb. The gene discussed is MCAM; the disease is colorectal carcinoma.