Example of p16^INK4A IHC staining in PeIN and primary PSCC Samples.

<p><b>(A)</b> Positive control—primary PSCC with HPV infection detected by INNO-LiPA assay <b>(B)</b> PeIN with weak cytoplasmic and nuclear staining (intensity score 1—classified as negative) <b>(C)</b> PeIN with moderate cytoplasmic and nuclear staining predominantly localized in the basal layer (intensity score 2—classified as negative) <b>(D)</b> PeIN with strong, uniform and confluent cytoplasmic and nuclear staining (intensity score 3—classified as positive).