We found U73122, Go6983 and U0126 significantly suppressed EGF-induced PN-1 up-regulation (Fig. 4g, h), and Go6983, a ubiquitous PKC inhibitor that can inhibit PKCα/β/γ/δ/ζ, could lead to a significantly inhibited EGF-induced PN-1 up-regulation (Fig. 4i), which suggested that PLCγ/PKC pathway could be involved in PN-1 up-regulation in breast cancer cells. This evidence concerns the gene EGF and breast cancer.