IGF1 and posterior cortical atrophy: Furthermore, there has been increasing focus on the potential of differential IGF-I isoforms actions through a putative E-peptide-specific signaling (Philippou et al., 2009; Quesada et al., 2009; Stavropoulou et al., 2009; Deng et al., 2011; Brisson and Barton, 2012) and particularly in PCa (Armakolas et al., 2010).