Expression of neuron specific enolase (NSE) in metastatic melanoma: Implications for progression of disease

5567 For immunotherapeutic treatment of organ-metastasized melanoma patients, we formulate melanoma cell vaccine from patients own tumor tissues. Antigen profiling is a critical aspect of immunotherapy. In view of well known heterogeneity of human melanoma, neither all tumor cells express all the antigens nor the antigens expressed by all cells are of same density. Very few studies have been undertaken to correlate antigen expression by the tumor cells used in vaccine with therapeutic outcome. Using a semiquantitative immunocytochemistry protocol, we have carried out antigen profiling of the autologous tumor cell vaccine. The following marker antigens were studied: CD20, CD24, CD33, CD34, CD44, CD117, CD133, CD166, ABCG2, Chk1, Chk2, 4-Oct, Muc-18, Neuron Specific Enolase (NSE), and Nestin in 27 cell lines. There are two aspects to these antigen markers. First, their prevalence or absence in the tumor tissue of the patient. Second, their prevalence or absence in the tumor cell vaccine administered to the patient. Both are critical to make correlation of antigen expression with survival. All cell lines have expressed uniformly CD44. Of other antigens, CD20, CD33, CD166, Muc-18, Nestin, and NSE were expressed at varying levels in these cell lines. The rest of the antigens (CD24, CD34, CD117, CD133, ABCG2, Chk1, Chk2, and 4-Oct) were negative in all cell lines. Expression of Nestin was seen in 26/27 cell lines with >25% cells in 21 and 25% cells in 24 and 25% cells in 14 cell lines whereas