MMP9 and breast cancer: And at the same time, in breast cancer, PRKCD could significantly enhance the invasiveness of tumor cells in vitro, which was tightly related to the activation of PRKCD after platelets stimulation and the up-regulation of MMP-9 induced by it, indicating that PRKCD played a pivotal role in mediating the tumor promotion after incubation with platelets, and targeting PRKCD to cut off the interaction between platelets and tumor cells was expected to be a potential therapeutic strategy for breast cancer [52].