Comparative analysis of BCL2, Cyclin D1, P53 and HMB45 expression in pigmented nevi and malignant melanoma of the skin, importance for diagnostic practice

Abstract

Pigmented tumors are a large group characterized by extensive morphological diversity, which makes their diagnosis difficult. There are malignant pigmented tumors morphologically mimicking benign lesions, as well as pigmented neoplasms with benign biological behavior and morphology mimicking malignant melanoma. Therefore, the use of non-melanocyte markers related to tumor growth and progression has long been used in diagnostic practice to help verify the malignant potential of tumors in morphologically complex tasks. The present study compares the expression of non-melanocyte markers BCL2, p53 protein, cyclin D1 synchronously with melanosome HMB45 in cutaneous pigmented neoplasms—benign nevi, atypical nevi, and malignant melanomas, in order to determine the significance of the expression as predictors of malignant potential. Immunohistochemically, 87 melanocyte lesions were studied—57 benign nevi, 6 atypical nevi, and 24 primary cutaneous melanomas with these markers. Daco reagents and an automated system for immunohistochemical marking of tissue sections and red chromogenic imaging were used. The results were reported according to 11 model schemes for evaluation of expression, providing accuracy in determining the immunoreactivity exhibited by each marker, increasing the certainty of the diagnosis. The results of the study showed that BCL2 expression in the three diagnostic groups has a wide range of overlap, which makes it unsuitable as a predictor of malignant potential. However, cyclin D1 and p53 protein show marginally opposite results between the groups of benign and malignant tumors. HMB45 also shows such a significant difference in expression between benign and malignant lesions. This allows them to be used as predictors of malignant potential in pigmented skin neoplasms, for greater reliability, in a triple combination—cyclin D1, p53 protein and melanosome clone HMB45, showing high statistical reliability.