Background: ProExC is a new marker for identification of precursor lesions of cervical carcinoma. Its utility in noncervical squamous cell carcinoma in situ (SCCIS) such as Bowen's disease (BD) and actinic keratosis (AK) where human papillomavirus (HPV) plays a role has not been elucidated. Our aim was to ascertain the immunohistochemical features and clinical utility of ProExC in SCCIS of the skin.
Methods: HPV presence was tested in SCCIS (38 BD and 7 AK) using GP5+/6+ and Short PCR fragment (SPF) primers and subsequently genotyped. Histopathologic sections were stained for ProExC and Ki67. A set of non-neoplastic skin proliferative lesions were included for immunohistochemical evaluation [14 psoriasis (PS) and 6 psoriasiform dermatitis (PSD)].
Results: HPV was detected in 18.9% BD. ProExC and Ki67 in the whole epidermis thickness was observed in 86.5 and 37.1% BD, respectively (p < 0.0001). ProExC and Ki67 were restricted to the lower third of the epidermis in PS and PSD.
Conclusions: ProExC expression is not associated with HPV in SCCIS of the skin. Proliferating cells are better delineated in SCCIS by ProExC which may be useful to assess the extent of these lesions. Different immunohistochemical profiles seen in neoplasic and non-neoplastic skin lesions suggest diverse alteration of cell-cycle kinetics.