Immunohistochemistry Analysis: Representative lot data. Paraffin-embedded human kidney (Fig. 1 and 2) and human breast (Fig. 3 and 4) tissues were prepared using heat-induced epitope retrieval in citrate buffer, pH 6.0. Immunostaining was performed using a 1:200 dilution of PP6R3. Reactivity was detected using the IHC-Select® Detection Kit. Positive cytoplasmic staining was observed in both human kidney and breast carcinomas.