RYK and mesothelioma: Since we have demonstrated that progranulin might activate EGFR and RYK in mesothelioma (Figs. 5 and 6) and considering that both EGFR and RYK might directly or indirectly modulate FAK activity [43–46], we asked whether progranulin-dependent regulation of FAK activity was mediated by EGFR and/or RYK.