Immunohistochemical expression of phospho-Akt in uveal melanoma.

The aim of this study was to evaluate the immunohistochemical expression of phospho-Akt and its possible association with clinicopathological features in uveal melanoma. Thirty-four enucleated eyes from 34 patients with choroidal melanoma were included in the study. Patients were divided into two groups based on the treatment received: (1) primary enucleation (n=18); (2) radiotherapy, either external beam or brachytherapy, and enucleation (n=16). Clinicopathological data were obtained. The minimum follow-up time was 72 months. Immunohistochemistry for phospho-Akt was performed using an anti-phospho-Akt (Ser 473) rabbit antibody. The association of phospho-Akt with clinicopathological parameters was investigated in each patient group separately. Phospho-Akt immunostaining was cytoplasmic in both groups. In the primary enucleation group, 10 tumours were phospho-Akt positive (55.5%). Patients with phospho-Akt-positive tumours were older (average 70.8 years versus 59 years, P=0.01) and phospho-Akt immunoreactivity was significantly associated with a higher risk of metastatic disease (Kaplan-Meier analysis, P=0.02). In the radiotherapy and enucleation group, nine tumours were phospho-Akt positive (56.2%). The absence of phospho-Akt expression was correlated with male gender (P=0.02). The following conclusions can be drawn from this study: (1) phospho-Akt immunoexpression was detected in 55.5% of uveal melanomas treated with primary enucleation and in 56.2% of uveal melanomas treated with radiotherapy and enucleation; (2) the association of phospho-Akt immunoexpression with clinicopathological features, including prognosis, merits further study.