This assumption is supported by the fact that even though the transporter NaPi2b is expressed in several normal tissues, the MX35 mAbs are accumulated predominantly in cancer cells, as demonstrated during the first clinical trials involving the pharmacokinetics, biodistribution, and intraoperative radioimmunodetection of radiolabeled MX35 in patients with advanced epithelial ovarian cancer (Rubin et al., 1993). This evidence concerns the gene SLC34A2 and ovarian carcinoma.