SYK and cyst: This suggests that ArQ-197 may induce growth inhibitory effects independently of its effects on the c-Met receptor tyrosine kinase, which is consistent with our previous observations.15 Our observation that cyst growth was reduced by IKK-α/β inhibitors suggests an involvement of the NFκB pathway, as previously described.35 Additionally, our results hint at the involvement of spleen tyrosine kinase (Syk), which, to our knowledge, has not previously been linked to PKD.