TP53 and progeroid syndrome: Overexpression of TP53 in mice, for example, is protective against cancer but associated with progeria, premature reproductive senescence, and early death; however, transgenic mice with a duplication of the TP53 locus that includes native regulatory elements are healthy and experience normal aging, while also demonstrating an enhanced response to cellular stress and lower rates of cancer (García-Cao et al., 2002; Tyner et al., 2002).