TP53 and breast cancer: Finally, in our study, the clinicopathological parameter that showed to be preferentially associated with the expression levels was the oral contraceptive administration, being linked with the overexpression of TP53, CCND1, FUS, YBX1 and PTBP1. In fact, the administration of oral contraceptive to domestic animals has been associated with an increased risk in developing tumours, including mammary tumours [62].