Features of matrix metalloproteinase-2 expression in the nuclei of tumor cells of a skin melanoma

Abstract

Goal of the study. To compare expression of matrix metalloproteinase-2 (MMP-2) in the nuclei and cytoplasm of tumor cells and assess the mutual relation between the localization of MMP-2 expression and different clinical and morphologic criteria in patients with a skin melanoma. Materials and methods. Tumor samples obtained from paraffin blocks taken from patients suffering from a skin melanoma and treated at the Krasnoyarsk Territorial Oncologic Dispensary served as the object of the study. Skin tissue samples taken from patients suffering from a skin melanoma (n = 44) were obtained from the Krasnoyarsk Territorial Pathological Anatomy Bureau. Immunohistochemistry was performed based on a standard technique using primary anti-matrix metalloproteinase-2 antibodies. Results. MMP-2 expression was revealed in the nuclei of tumor cells of a skin melanoma in 43.1% of cases and in the cytoplasm in 56.9% of cases. No significant differences in MMP-2 expression in the nuclei and cytoplasm were revealed (p = 0.33). Patients with nuclear expression in tumor cells are characterized by a more favorable prognosis than patients with cytoplasmic enzyme expression in tumor complexes. No dependence of the intracellular localization of MMP-2 expression on the patient sex or age, tumor localization, Clark level of invasion, Breslow’s thickness, particular features of tumor lymphocyte infiltration, tumor growth phase, histological subtype, pigmentation, tumor ulceration and tumor stage according to AJCC (American Joint Committee on Cancer) was revealed. Conclusion. MMP-2 located in the nuclei can be related to hypoxia in the tumor tissue as well as increased peroxynitrite level, which, in its turn, can have an effect on the function and regulation of matrix metalloproteinases. Moreover, MMP-2 with an atypical localization can be related to tumor cells with different biological characteristics within the same tumor, which characterize the intratumoral heterogeneity of neoplasms. The biological and clinical role of changes in the intracellular localization of the enzyme needs further explanation.