Circulating tumor cells (CTCs) have gained importance in the oncology field as biomarkers of tumor development. The most relevant observation that emerged from the recent studies on CTCs is their heterogeneity, which can be investigated by new technologies for single cell analysis. Areas covered: This review considers the most recent advances (limited to the last two years) in the mutational analysis of single CTCs with a critical point of view on the technical challenges still to be faced and the steps needed to reach a standardization of the procedures able to translate these new approaches into clinical practice. Expert commentary: CTCs represent a surrogate tumor sample obtained by a minimally invasive procedure allowing the serial monitoring of the patient during the follow-up period or after treatment. Notwithstanding that, the analysis of CTCs is not so widespread; in fact, a limited number of centers can be equipped and possess the expertise for the development of workflows able to identify, enrich and isolate CTCs from blood. Moreover, the lack of standardized procedures and guidelines limits the study of CTCs to 'research use only' approaches.
Keywords: Cancer; circulating tumor cells; liquid biopsy; single cell; somatic mutations; whole genome amplification.