NANOG as prognostic factor of prostate cancer course

The variability of the clinical course of prostate cancer (PC) indicates the need to find factors that could predict the aggressive potential of neoplasms accounting the biological characteristics of tumor cells. In this context, the role of NANOG, a transcription factor involved in maintaining pluripotency and one of the markers of cancer stem cells (CSCs), is being actively studied today. AIM: To investigate the level of NANOG mRNA in tumor tissue of patients with PC and to analyze the possibility of its use as a marker of the disease course. MATERIALS AND METHODS: The study involved 85 patients with PC of stages II-IV. Morphological and immunohistochemical studies were performed on serial paraffin sections of resected PC using monoclonal antibodies to Ki-67 and androgen receptor. NANOG and miR-214 mRNA expression in tumor cells was analyzed by real-time reverse transcription polymerase chain reaction. The identification of CSCs was performed by double-labeled immunohistochemical method using primary antibodies to CD24 and CD44. RESULTS: We have revealed notable variability of NANOG mRNA levels in tumor tissue of patients with PC (mean 4.18 ± 0.65 a.u. with individual deviations from 0.11 ± 0.03 a.u. to 15.24 ± 0.36 a.u.). According to NANOG mRNA levels, two groups of the PC patients were delineated: group 1 and group 2, with the average NANOG mRNA levels of 2.12 ± 0.16 a.u., and 8.68 ± 1.24 a.u., respectively. The NANOG mRNA levels in tumor tissue of PC patients of groups 1 and 2 correlated with preoperative serum prostate-specific antigen level (r = 0.58; p < 0.05 and r = 0.64; p < 0.05, respectively), tumor volume (r = 0.42; p < 0.05 and r = 0.72; p < 0.05, respectively), regional lymph node metastases (r = 0.70; p < 0.05 and r = 0.75; p < 0.05, respectively). High NANOG mRNA levels in tumor cells were associated with such molecular and biological features of PC as androgen receptor expression (r = 0.52; p < 0.05), high proliferative activity (r = 0.60; p < 0.05) and the presence of CSC markers (r = 0.75; p < 0.05). CONCLUSIONS: The findings indicate that NANOG is involved in the formation of the PC malignancy and should be further studied as a potential marker for the prediction of the disease course.