Correlation of CCND1 , ID1 , SNAI1 and SNAI2 expression to recurrence free survival. Expression of our genes of interest in relation to recurrence-free survival was examined in a breast cancer database containing 1,107 tumours from Sims et al. (2008). Gene expression intensity was quartiled as 1-low, 2- medium low, 3- medium high and 4- high, and assessed in all patients, ER-positive and ER-negative patients, respectively (A) CCND1 quartiles (B) ID1 quartiles (C) SNAI1 quartiles (D) SNAI2 quartiles. P-value is based on log-rank test.