PPP1R1B probe 1 expression was not associated with breast cancer specific survival of ER positive patients; however, low expression of PPP1R1B probe 2 and 3 were both associated with adverse survival of ER positive breast cancer patients (P = 0.041 and P = 0.002 respectively) (Fig. 3B,C). This evidence concerns the gene PPP1R1B and breast cancer.