The identification and differential expression of calcium-binding proteins associated with ocular melanoma.

Calcium-binding proteins may endow tumor cells with properties related to their malignancy and metastatic phenotype. Chromatographic procedures and amino acid sequence analysis were used in this study to identify seven calcium-binding proteins, annexin VI, cap g, annexin V, calmodulin, S100A11, S100B and S100A6, associated with uveal melanoma, the primary ocular tumor of adults. This series of calcium-binding proteins was identified in both primary tumors and cell lines of uveal melanoma. Several of the proteins were shown by immunochemical methods to be differentially expressed between normal uveal melanocytes and malignant melanomas of the uvea. In addition, the expression of S100A6 may correlate with the malignant properties of the tumor.