YB-1 is associated with BCSS in all subtypes of breast cancer. YB-1 is expressed in 23.1% (480/2078) of luminal A and 51.6% (95/183) of luminal B, and is more likely to be expressed in the ER-negative breast cancers, in which it was found in 64.6% (320/493) and 66.4% (148/223) of TNP and HER-2 subtypes, respectively. Its expression is associated with poor survival in all subtypes of breast cancer. 'N' represent of number of YB-1 positive patients who died from breast cancer (number of events) in each subtype. Examples of the immunostaining are represented in the inset (magnification 200×). BCSS, breast cancer specific survival; ER, estrogen receptor; YB-1, Y-box binding protein-1.