PAK1 and Patent ductus arteriosus: More importantly, we have shown that depletion of PAK1 reduced PSC-stimulated PDA cell proliferation, migration/invasion, suppressed intrinsic and PSC-stimulated PD-L1 expression, and attenuated PSC-mediated protection of PDA cells from cytotoxic lymphocyte-induced cell death, indicating a key role of PAK1 in modulating PSCs activity and anti-tumour immune response in the TME of PC [8].