The INT6+ site is directly flanked by a short PolyA motif and such sites represent potential recognition sites of hnRNP (heterogeneous nuclear ribonucleoprotein) splicing factors. The predicted hnRNP binding pattern at INT6+ depended indeed on the INT6+ haplotype, when predicted by web-based algorithms, and their binding preference and activity, in concert with other splicing or transcriptional regulators, may ultimately be the basis of the splicing changes observed here (Piva et al., 2012; Carrillo Oesterreich et al., 2011; Reddy et al., 2013).