INTRODUCTION

Inverting follicular keratosis is a rare tumor with an unknown etiology. Clinical manifestations can mimic many epithelial skin neoplasms. The possibility of malignant transformation of the tumor is not well investigate.

THE PURPOSE

Was to study the features of the expression of p53 protein and the marker of proliferative activity of cells Ki-67 with inverting follicular keratosis.

MATERIAL AND METHODS

Under observation were 3 patients with inverting follicular keratosis aged 75–79 years with the localization of neoplasms on the skin of the face. The diagnosis in all patients was verified by histological analysis of the skin. Immunohistochemical tests were performed using monoclonal antibodies to p53 protein and the Ki-67 cell proliferative marker.

RESULTS

In all cases, a positive reaction with monoclonal antibodies to the p53 protein was diffuse and was detected in the nuclei of more than 30% of tumor cells. When studying the proliferative activity of cells with monoclonal antibodies to the Ki-67 marker, only the nuclei of basaloid cells located on the border of tumor complexes were stained. Expression of the Ki-67 marker was detected in 19–20.7% of basaloid cells, indicating a low level of their proliferative activity.

CONCLUSION

The peculiarities of the expression of p53 protein and the Ki-67 cell proliferative activity marker suggest that the morphogenesis of inverting follicular keratosis is associated not only with the proliferation of keratinocytes, which is quite low in the tumor, but with the «aging» of the cells and the violation of their differentiation. The «aging» of cells, presumably due to the activation of suppressor genes and accompanied by an irreversible delay in cell division, is a kind of «protection» from malignisation of tumor.