PAK1 and breast cancer: Group A Paks are also involved in breast cancer and Her2Neu signaling, particularly Pak1.14, 15, 16, 17, 18, 19, 20 The focus of study is Pak4, but in the future it will be important to use similar techniques to examine the roles for other Pak family members in breast cancer, and to determine whether Pak4 may act in conjunction with other Paks in cancer, or if different Pak family members operate in different types of breast cancer or at different stages.