Antibody specificity determination by peptide competition: (A) Serial
sections of CRC-FFPE slides were immunostained with anti-topoI-pS10; (B and
C) Slides from the tissue were immunostained with anti-topoI-pS10 in the
presence of a phosphopeptide against which the antibody was raised. Two
different concentrations: 250 and 500 nm phosphopeptide (Fig. B and C,
respectively) were used for this absorption assay. (D) Serial section of
gastric cancer FFPE slides were immunostained with anti-topoI-pS10. (E and
F) Tissues were also immunostained with anti-topoI-pS10 in the presence of
topoI-non-phosphopeptide peptide. Two different concentrations: 250 and 500
nm (Fig. E and F, respectively) were used for the IHC absorption assay.
Scale bar = 100 µm. Abbreviations: topoI-pS10, topoisomerase I
phosphorylates at serine 10; CRC, colon cancer; FFPE, formalin-fixed
paraffin embedded.