The differential impact of staining for AGR2 on prognosis in ERα-positive and ERα-negative patients is in contrast to the adverse effect of staining for S100A4 and OPN on the survival of patients with breast cancer which are apparent in both ERα-positive and ERα-negative subgroups (Rudland et al, 2000, 2002). Here, S100A4 is linked to breast carcinoma.