p53 Protein overexpression in verrucous carcinoma of the skin

Verrucous carcinoma is a rare variant of well-differentiated squamous cell carcinoma which is characterized by a marked local aggressivity and a poor metastatic potential. Until now, little has been known about the oncogenic mechanisms of this tumor. Recently, extensive investigations have shown that p53 protein, a nuclear protein with oncogene-suppressing activity, may play a crucial role in cell transformation and immunoreactivity for this protein is found in a wide variety of cancers.

The aim of the present study is to examine the frequency of immunohistochemically detectable p53 protein by using two monoclonal antibodies (D07 and BP53-12) in 8 cases of formalin-fixed and paraffin-embedded specimens of verrucous skin carcinoma.

Overexpression of p53 protein was detected in 6 (75%) of the cases examined with the D07 antibody and in 5 (62.5%) cases with BP53-12. The p53 positivity was shown in a peripheral distribution affecting mainly the basal cell layers of tumoral islands.

In a high percentage of verrucous carcinoma, p53 immunoreactivity has not been previously described in the literature and our findings suggest that abnormal expression of p53 tumor suppressor protein is a common event in the pathogenesis of this tumor.