This phenotype aggravated with age, concomitant to the decline in STAT5 signaling and up-regulation of AKT and ERK1/2 signaling, therefore it is possible that a similar mechanism as described in breast cancer contributes to the signaling shift observed in the prostates of ageing Pb-PRLSTAT5f/f mice. The gene discussed is STAT5A; the disease is breast carcinoma.