Identification and characterization of the extracellular vesicles secreted by rectal cancer and their relation with the response to neoadjuvant treatment

Abstract

Despite some similarities, the rectal cancer has characteristics that differentiate it from the colon cancer, resulting in different treatments and outcomes. The rectal cancer in stages II and III, is treated with neoadjuvant chemoradiation followed by surgery, and the response to neoadjuvant treatment in patients is variable and unpredictable. Up to now, surgery intervention is required to assess the pathologic response to therapy. The identification of predictive biomarkers for response to therapy is of great importance, in order to identify the patients that will benefit from such treatment. Extracellular vesicles (EVs) secreted by tumors cells have been described to participate in tumor growth, as well in invasion and metastasis. In addition they can also be an important source of predictive biomarkers for response to therapy. The EVs secreted by rectum cancer are poorly characterized and their role in the tumoral process in unknown. Thus, our objectives are: 1- identification and characterization of extracellular vesicles secreted by rectal cancer cell lines and their role in the resistance to radiotherapy and chemotherapy; 2- to identify and characterize the extracellular vesicles secreted into the blood of patients with rectal tumors as a predictive factor of pathologic response to neoadjuvant chemoradiation. (AU)