Abstract

Abstract Background: There is continued interest in markers indicative of circulating melanoma cells. Nestin is a neuroepithelial intermediate filament protein that was found to be expressed in melanoma and in various cancer stem cells. Objective: We investigated expression of nestin in peripheral blood of melanoma patients. Patients/Methods: We analyzed nestin expression by flow cytometry and by quantitative reverse transcription polymerase chain reaction (qRT-PCR) both in tissues (n=23) and blood samples (n=102) from patients with AJCC stage III-IV melanoma. Forty-six negative controls were also added. Results: Flow cytometry did not reveal nestin expressing cells in peripheral blood of healthy volunteers. In melanoma patients, however, nestin protein was expressed in a proportion of melanoma cells enriched from peripheral blood by immunomagnetic sorting. In melanoma tissue samples a significant correlation was found between mRNAs encoding for nestin and tyrosinase (p=0.001) and Mart-1 (p=0.002), whereas in blood a significant correlation was only observed for tyrosinase (p=0.015), but not for Mart-1 (p=0.53). Nestin expression was higher in stage IV patients compared to stage III/IV with no evidence of disease (NED), positively correlated to tumour burden, and positively correlated to expression of tyrosinase and Mart-1. Conclusions: Nestin showed to be an additional marker of interest for circulating melanoma cells. Prospective studies have to investigate a potential added informative value in comparison to markers already in use for melanoma cell detection.