MP7-16 MOLECULAR DIAGNOSIS OF LYMPH NODE METASTASIS IN PATIENT WITH UPPER URINARY TRACT CANCER WHO HAD EXTENDED LYMPHADENECTOMY

INTRODUCTION AND OBJECTIVES: In patients with upper urinary tract urothelial cancer (UTUC), the significance of lymphadenectomy not only in diagnostic aspect but also in therapeutic benefit has not been clarified yet. In order to examine its significance, we are currently conducting a prospective clinical trial of extended lymphadenectomy in patients with UTUC. Furthermore, we applied qRT-PCR technique to retrieved lymph nodes by extended lymphadenectomy in patients with UTUC for more accurate and sensitive diagnosis. In addition, We examined the association with the clinicopathologic findings and prognosis. METHODS: We included 41 patients with UTUC who underwent extended lymphadenectomy. Tissue sections of retrieved LNs from each patient were divided in two parts. One of them was assessed by qRT-PCR assay, and the other one was assessed by routine pathological examination. Four kinds of molecules (FXYD3, KRT19, KRT20, UPK2) were selected as markers to detect urothelial cancer cells. In addition, about a representative sample, We performed the immunohistological examination in order to perform a supplementary examination of the qRT-PCR result. We regarded specimen in which all marker molecules was positive as presence of micrometastasis. RESULTS: As total, 21 out of 738 LNs (2.8%) showed amplification of all marker. In 4 out of 41 patients (9.8%), LN metastasis was confirmed by not only qRT-PCR but also by histological examination. In 7 patients (17.1%), amplification of all marker genes was observed by qRT-PCR without evidence of metastasis by histological examination, indicating the presence of micrometastais. Based on this result, We divided the 41 patients into three groups and evaluated the association with conventional prognostic factors or progression free survival. qRT-PCR findings was associated with the lymphovascular invasion (p