Colorectal carcinomas in 2013: the search for powerful prognostic markers is still on the go!

Colorectal cancer (CRC) is the third cause of cancer worldwide after prostate cancer and breast cancer. Patients have a survival rate of 5 years, which varies between 10 and 95% depending on CRC stage. Today, the management of patients with CRC is based on parameters such as TNM and classic histologic parameters, but new molecular and cell markers have been created to improve treatment and survival. Determining the expression of a characteristic set of genes either from formalin-fixed paraffin-embedded tissue (Onco type DX test™) or from fresh tissues (AGENDIA© ColoPrint®) has led to encouraging results, but there is a need for clinical validation on a large number of patients. Also, next-generation sequencing (NGS) technologies may be the next step in the molecular approach of CRC tumor samples, allowing tumor characterization by gene signature arrays. In addition to molecular markers, evaluation of the presence of cellular markers such as circulating tumor cells (CTC) in the blood of patients with CRC can optimize prognostic evaluation and response to treatment. CTC isolation methods used today have different sensitivities and specificities, due not only to the very small number of these cells but also to the epithelial-mesenchymal transitional process (EMT). This paper presents the preliminary results of our study conducted on CTC isolation in patients with CRC by filtration method (Screencells Cyto®). This fast and efficient method identifies CTCs and also isolates cells in EMT, which explains its high efficiency compared to technologies based on immunomagnetic and microfluidic separation reliant on EpCAM presence on the cell surface.