Aging clock: the watchmaker's masterpiece

The phenomenon of cellular senescence has been known for almost four decades. Yet, until very recently, the molecular mechanisms that lead to senescence have been poorly understood. However, substantial progress has been made in the last few years toward identifying the pathways executing senescence. This r view focuses on two major advances ill this field, the telomere aging clock theory and the cell cycle regulatory mechanisms in senescent cells. These recent studies indicate that cellular senescence is a highly elaborate and active process, which presumably works as an anti-oncogenic mechanism.