“…Detection of biological markers in the blood stream is not a new concept. For example, for many years the carcinoembryonic antigen (CEA), the prostate-specific antigen (PSA) or the Ca-125, among others, were used to assess the treatment response (Friedrich, 2017), defining the conduct subsequently taken, whether the clinical follow-up, maintenance of the treatment initially applied or even the search for an alternative treatment given the lack of response, which was observed with the marker increase (Murray et al, 2015;Stremitzer et al, 2015;Alexandre et al, 2012). The plasma genotyping has the potential to bring a higher number of information, not only about the decision of whether to treat or not treat, but also about how to treat or how to optimize the treatment response.…”