To identify variants in the SLC34A2 gene, which encodes the NaPi2b transporter, genomic DNA sequencing was performed on samples obtained from the peripheral blood of 64 patients with malignant neoplasms (ovarian carcinoma (n = 27), breast cancer (n = 20), and renal cell carcinoma (n = 17)) receiving treatment at the Republican Clinical Oncology Dispensary named after M.Z. Sigal in Kazan, Russia. The gene discussed is SLC34A2; the disease is ovarian carcinoma.