SERBP1 mRNA is expressed in breast epithelial cells but not in stromal cells as shown by non-radioisotopic in situ hybridisation SERBP1 expression was investigated by non-radioisotopic RNA in situ hybridisation in a subset of normal (n = 10) and cancerous (n = 10) breast tissue samples derived from the initial TMA set. (A, B) Normal breast tissue with moderate SERBP1 mRNA expression in the epithelial cells (arrow) and no stromal (asterisk) staining using antisense SERBP1 RNA. (B) Insert shows no staining by SERBP1 sense RNA. (C, D) Invasive breast carcinoma (here: ductal type) also revealed moderate SERBP1 mRNA expression in the epithelial cells (arrow) applying antisense SERBP1 RNA whereas no staining could be seen in stromal cells (asterisk) (D) Insert shows negative staining by SERBP1 sense RNA. Magnifications: A, C: 40x; B, D: 200x.