Immunohistochemical characteristics of uveal melanoma assording to the age at diagnosis, histological type and extension of the tumor.

The purpose of this study was to investigate the relationship between MMP9 expression and tumour invasion in different structures of the eye. We also examined whether there was any correlation between the growth factors (TGFb and EGF), onco-suppressor proteins (p16 and p53) and Ki-67, and the tumour histological subtypes, atypia level and age at diagnosis. Tumour specimens were obtained from 42 primary uveal melanomas immediately after enucleation at The Helmholtz Moscow Research Institute of Eye Diseases. The patients were not treated with radio- or thermotherapy. During our systematic study, we exclusively employed 10%-formalin fixed, paraffin-wax-embedded tissue sections of UM for histological diagnosis and immunohistochemistry. According to our data the hyperexpression of MMP9 and EGFR correlates with a high proportion of spindle cells in a tumour (Kruskal-Wallis test p=0,1 for each). Moreover, we have demonstrated the association between the level of EGFR, TGFb and MMP9 expression and the initial invasion stage (Spearman's test p=0,1). In addition, we have revealed the significant correlation between TGFb hyperexpression and atypia level (Spearman's test p=0,059). Our data reflect that the diagnoses at an advanced age correlate with hyperexpression of p16 (Kruskal-Wallis test p=0,068). An interesting result is that p16 level reduced in inverse proportion to that of TGFb. On the basis of our data and previous studies, we reached the conclusion that after the lapse of time the level of p16 rises significantly in order to inhibit proliferating activity of melanocytes in the normally functioning pigmented layer. However, although the probability of UM diagnoses in elderly is increasing, we have no reliable data for the relationship with high atypia levels.