After the Id1-RNAi-LV construct was transfected into EPCs of 6 patients with ovarian cancer, integrin α4 mRNA expression levels in transfected cells were compared to those in nontransfected and control-transfected (NC-GFP-LV) EPCs of 6 patients with ovarian cancer by quantitative RT-PCR. This evidence concerns the gene ID1 and ovarian carcinoma.