Molecular diagnosis of lymph node metastasis in patients with upper urinary tract cancer who underwent lymphadenectomy

Objectives To determine the significance of molecular diagnosis of lymph node metastasis using quantitative reverse transcription polymerase chain reaction in patients with upper urinary tract urothelial cancer. Methods A total of 51 patients with upper urinary tract urothelial cancer who underwent extended lymphadenectomy were included in the present study. Retrieved lymph nodes from each patient were divided into two parts. One part was assessed by quantitative reverse transcription polymerase chain reaction assay for molecular staging, whereas the other one was assessed by routine histopathological examination. Four kinds of molecules (FXYD3, KRT19, KRT20 and UPK2) were selected as markers to detect urothelial cancer cells. Results The average number of retrieved lymph nodes was 18.3. As UPK2 showed the best discrimination ability among four markers, the patients were classified in three categories according to UPK2 expression: N(+)PCR(+) for patients who had lymph node metastasis by routine pathological diagnosis as well as quantitative reverse transcription polymerase chain reaction (n = 4); N(−)PCR(+) for patients who had lymph node metastasis by polymerase chain reaction but not by routine pathological diagnosis (n = 7); and N(−)PCR(−) for patients who showed no lymph node metastasis not only by routine pathological diagnosis but also by polymerase chain reaction (n = 40). The prognosis of the N(−)PCR(+) group was better than that of the N(+)PCR(+) group, and similar to that of the N(−)PCR(−) group. Conclusions Quantitative reverse transcription polymerase chain reaction could detect micrometastasis in patients with upper urinary tract urothelial cancer. However, the prognosis of patients with micrometastasis is better than patients with pathologically metastasized lymph nodes, and similar to patients without micrometastasis.