PTK2 and cancer: Further hierarchical protein‒protein interaction26 analysis of these 35 genes (Supplementary Fig. 2e) revealed that fibronectin 1 (FN1) had higher numbers of interactions with other proteins and splicing events, suggesting that FN1, a protein associated with cancer aggressiveness through modulation of the FAK/AKT pathway, is a hub gene in the PRPF8 pathway (Fig. 5f).