Antigen Sniffs Out Melanoma.
MIAMI -- Testing for a newly identified melanoma antigen appears to identify patients who have residual disease after excision of the primary tumor, Rishab K. Gupta, Ph.D., said at the annual science writers seminar sponsored by the American Cancer Society.
Tumor antigen 90 (TA-90), a 90-kd glycoprotein, appears on the surface of melanoma cells and can be identified using an enzyme-linked immunoassay for the TA90 antigen-antibody complex in blood, said Dr. Gupta of the division of tumor markers and immunodiagnosis at the John Wayne Cancer Institute, Santa Monica, Calif.
In a study of 57 patients with subclinical melanoma metastases after excision of the primary tumor, 43 had a positive assay for TA-90, Dr. Gupta said.
Follow-up studies showed a 5-year survival rate of 63% for TA-90-positive patients and 88% for TA-90--negative patients.
With sensitivity of 77% and specificity of 76%, TA-90 is less than the ideal for identification of individuals with residual disease, but is substantially better than other tumor markers for melanoma that have been under study, Dr. Gupta said.
Ongoing investigations are aimed at identification of a combination of TA-90 and other markers that might improve the sensitivity and specificity of the test.
The degree of accuracy achieved with TA-90 appears to support its use for selecting which patients without clinical evidence of disease are candidates for trials of postoperative immunotherapy with the new polyvalent vaccine, Dr. Gupta said.
The TA-90 research has been, supported by the National Institutes of Health and institutional funds, and the test is not yet under development as a commercial product, but as more data are collected from ongoing research it is expected that it will attract commercial interest, he added.
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|Author:||Branch, David R.|
|Publication:||Family Practice News|
|Date:||May 15, 1999|
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