Abstract
Purpose: :
Alpha-B-crystallins are members of the small heat-shock protein family (sHsps) and have properties such as interaction with cytoskeletal proteins, DNA binding and antiapoptotic activity in normal and malignant cells. Alpha-B-crystallin expression is a marker for poor prognosis in squamous cell carcinomas of the head and neck region and predicts poor clinical outcome in breast cancer. However, several studies showed an inhibitory role for sHsps on tumour proliferation and an inhibitory role in tumour progression. The evaluation of the immunohistochemical profile of alpha-B-crystallin in uveal melanoma (UM) may help to elucidate its role in this tumor.
Methods: :
Thirty-one cases of paraffin-embedded human UM were immuno-stained with a Alpha-B-crystallin monoclonal antibody using the Ventana BenchMark fully automated machine. Clinical-pathological data were obtained, including age, gender, cell type, and largest tumor dimension and further correlated with alpha-B-crystallin expression. The survival rates of patients were assessed using a Kaplan-Meier test.
Results: :
The expression of alpha-B-crystallin was positive in 18 (58%) specimens. Staining pattern was diffuse in 10 (55.5%) and focal in 8 (44.5%) cases. Positive immunostaining for alpha-B-crystallin, was associated with better survival rate (Kaplan-Meier test p=0.0037). The expression of alpha-B-crystallin was not correlated with other prognostic factors. The percentage of positive cases in the group of patients irradiated prior to enucleation was higher when compared with enucleated group (p< 0.0001).
Conclusions: :
To the best of our knowledge this is the first study examining the expression of alpha-B-crystallin in uveal melanoma. The majority of cases expressed alpha-B-crystallin. High expression of alpha-B-crystallin may reflect irradiated or non-irradiated oncogenic stress in this tumor. The association between expression of alpha-B-crystallin and a better survival rate suggests that alpha B-crystallin plays a regulatory role in uveal melanoma cellular proliferation. Our results warrant further studies on this particular role of alpha-B-crystallin in uveal melanoma.
Keywords: melanoma • crystallins • immunohistochemistry