Expression of p16 in Conjunctival Intraepithelial Neoplasia Does Not Correlate with HPV-Infection

The aim of our study was to identify the frequency of expression of p16(INK4a) (CDKN2A) and HPV (human papilloma virus) in different grades of conjunctival intraepithelial neoplasia (CIN). Twelve specimens including CIN I (2), II (3), III (5), and CIN with beginning invasion (2), as well as 15 control specimens, were stained with antibodies against p16(INK4a) and MIB1. The presence of HPV was examined by PCR. p16 as well as MIB1 were significantly elevated in CIN compared to control specimens (p<0.01) without correlation with the differentiation grade. Only two cases with CIN grade 3 contained HPV 16. As few control specimens also showed increased p16(INK4a) expression, p16(INK4a) seems not to be a very reliable marker for the exact determination of CIN. It could serve as an additional diagnostic tool besides the morphological characterization. Our study suggested that p16(INK4a) elevation is not associated with HPV infection.