TP53 and breast cancer: This finding suggests that p53 is involved in the prevention of pathological proliferation by promoting asymmetric division, thus contributing to increased differentiation.60 It is also consistent with many scientific data regarding the role of p53 mutation in breast cancer development.61 Interestingly, MaSCs subjected to 4.0 Gy irradiation showed 2.7 fold increase in mammosphere reconstitution capacity, confirming that X-ray increases MaSCs proliferation.62