TP53 and breast cancer: IHC detection of p53 protein is therefore loosely, but imperfectly, associated with mutations in TP53. Some studies assessing p53 status using either IHC or mutational analysis have concluded that TP53 mutation is associated with poor prognosis, but other authors have reported no impact of TP53 mutation on outcome in early breast cancer, and the evidence is not sufficiently strong for p53 status to be recommended as a marker in routine clinical practice [4].