VEGFA and cancer: The total plasma or serum VEGF concentration is used as an in vivo marker, and to date, its true association with the efficacy of bevacizumab for treating cancer in humans is uncertain, as the results of studies assessing the predictive value of serum VEGF levels for treatment outcomes have been not consistent (Presta et al., 1997; Bernaards et al., 2010; Tang et al., 2016).