Abstract
Abstract: :
Purpose:Recent studies have demonstrated the close link between oncogenesis and cell cycle machinery. We studied the expression of cyclin D1, cyclin–dependent kinase inhibitory protein –P21/waf in choroidal melanomas and an attempt was made to correlate their levels with light microscopical prognostic parameters and with proliferative index Ki–67. Methods:Immunohistochemistry was performed on 100 formalin–fixed, paraffin–embedded specimens of malignant choroidal melanoma. Prognostic histological markers such as cell type, largest tumor dimension (LTD), mitotic figures, tumor infiltrating lymphocytes (TiL), micro vascular pattern and Ki 67 index were studied. Tumors were divided into 2 groups. Group A: Tumors with no extrascleral extension and no liver metastasis (n=81) Group B: Tumors with extrascleral extension or liver metastasis (n=19) Results:In–group A (n=81) there were 39 spindle cell, 35 mixed cell and 7 epithelioid cell melanomas. LTD > 10 mm seen in 62 tumors, mitosis absent in 80 tumors, TiL negative in 70 tumors, nuclear grade < III seen in 77 tumors and none had closed loop vascular patterns. Cylin D1 < 1% was observed in 63 tumors, 1–5% cyclin D1 positivity was observed in 18 tumors. P21 < 1% was observed in 75 tumors and 5 tumors had P21 between 1–5% and in 1 tumor P21 was > than 10%. Ki 67 index > 50% seen in 1 tumor. In–group B tumors (n=19) there were 3 spindle cell, 13 mixed cell and 3 epithelioid cell melanomas. LTD > 10mm seen in 15 tumors, mitosis absent in 16 tumors, TiL negative in 11 tumors, nuclear grade < III seen in 15 tumors and closed loop vascular pattern seen in 4 tumors which had metastasized to the liver. Cyclin D1 < 1% was seen in 15 tumors and 4 tumors had cyclin D1 between 1–5%. P21 was less than 1% in all 19 tumors. Ki 67 index was < 50% in all 19 tumors. Group A tumors showed no correlation between Ki 67 and cyclin D1, but cyclin D1 and P21 showed significance. (p =0.035) There was no correlation between Ki 67, cyclin D1 and P21 in–group B tumors. Conclusions:Thus uveal melanomas have a low cyclin D1, P21 and Ki 67 index. They could not be correlated with conventional light microscopical prognostic markers and between the 2 groups.
Keywords: immunohistochemistry • tumors • melanoma