Cellular senescence, an inevitable biological process that results in organismal ageing as well as age related diseases (3). The Bae et al. asked themselves a variety of questions that could lead into possible mediation of cellular senescence. They first started with stem cells. Is there a way we can utilize stem cells to further study this phenomenon? How can we further understand the secretory factors and their corresponding pathways that exhibit anti senescence-like effects within embryonic stem cells in humans? Due to these questions, the authors decided to perform a real-time PCR analysis, Western Blot, and an Antibody Array on their conditioned medium groups that contained mouse embryonic stem cells. This ultimately became the PDGF/FGF pathway (Platelet Derived and Fibroblast Growth Factor). Bae et al. first conditioned embryonic stem cells obtained from mice. Both of the significant molecules were PDGF -BB and FGF 2. Both of which, play a crucial role within the PDGF/FGF pathway due to their regulation of cell growth and development (4). A culture of stem cells (mESC-CM) along with human dermal fibroblasts (HDFs) was done, then analysis of these factors were done through real time PCR as well as an Antibody Array. Together, these results lead Bae et al. to the conclusion that PDGF -BB significantly reduced SA-b-gal activity and increased cell proliferation. PDGF -BB was also examined to upregulate the activity of FGF 2. After further examination of PDGF -BB within the PDGF pathway, they determined that FGF 2 was the ultimate inducing effect of PDGF -BB in Human Dermal Fibroblasts . To these results, it was concluded that PDGF -BB plays a critical role in presenting an anti senescence effect through the upregulation of FGF 2. To continue, the anti senescence effect of H-CM (High activity Conditioned Medium), one of their experimental groups as a result of mESC-CM, is mediated through PDGF -BB signaling.