CD4 and cancer: There are three main conclusions in this study: 1) Low alteration frequency was observed in colon and gastric cancer; 2) High CD44 mRNA was found in colon and gastric cancer than that in matched normal tissues, and it correlated with a benign survival rate in gastric cancer; 3) CD4 and CD74 may be used as markers to predict the prognosis of colon and gastric cancer, but not the markers for cancer stem cell.