PRF1 and breast carcinoma: Meanwhile, SB203580, an inhibitor of p38 MAPK pathway, blocked the increased MICA/B expression of LA-pulsed DCs (Fig. 4g), and the increased secretion of perforin, granzyme-B, IFN-γ, as well as cytotoxicity of LA/DC-induced NK cells against breast cancer (Fig. 4h).