PTEN and neoplasm: This is important given the critical role of the PI3K pathway in promoting senescence bypass in fibroblasts (Kennedy et al. 2011), as well as in melanoma, where loss of PTEN can cooperate with activated BRAF or NRAS to promote tumor initiation and metastatic dissemination (Nogueira et al. 2010; Vredeveld et al. 2012).