S100A1 and breast cancer: Hatoum et al. identified differential regulation of the annexin/S100A family by activation of p14ARF-p53-p21 in breast cancer cells, and demonstrated that ANXA1, ANXA2, ANXA4, ANXA6, and ANXA9 were upregulated, with a high expression of ANXA9 functioning as a predictor for poor OS after endocrine therapy in estrogen receptor-positive (ER+) patients [57].