Importance of antibody validation in detecting cell cycle regulatory protein p16 INK4A by immunohistochemistry on pancreas tissue

Aims/Objective p16INK4A is a cyclin-dependent kinase inhibitor that plays important roles in pancreatic islet beta-cell maturation, function, and senescence. As staining pattern consistency and reproducibility have been challenging in the field, our objective was to validate a monoclonal antibody for the detection of p16INK4A in mouse and human fixed pancreas sections.Methods Four commercial monoclonal antibodies reported to react against mouse p16INK4A were tested by fluorescent immunohistochemistry on positive and negative control formalin-fixed paraffin-embedded pancreas sections from two different mouse strains. Lot-to-lot consistency was also evaluated. Fixed human donor pancreas sections were evaluated for reactivity with the monoclonal p16INK4A antibody that performed best on mouse tissues.Results One commercial monoclonal antibody robustly detected a nuclear antigen in both mouse and human pancreas sections, consistent with the previously reported p16INK4A staining pattern, and its role as a cyclin-dependent kinase inhibitor in beta cells. This antibody also showed lot-to-lot consistency in staining pattern.Conclusion Our findings highlight the importance of antibody validation for p16INK4A detection in mouse and human pancreas sections and suggest caution in using untested commercially available antibodies to this protein for immunohistochemistry of the pancreas.