The CancerWeb Report, What's New In Cancer: January, 1996: Melanoma

• Response of melanoma to interferon - Interferon alpha-2b is the first agent to show significant benefit in terms of relapse-free and overall survival, according to a report of the Eastern Cooperative Oncology Group. There was a median increase in disease-free survival from 1 to 1.7 years, and in overall survival from 2.8 to 3.8 years. There was also a 42% improvement in the fraction of patients continuously disease-free after treatment with interferon. (Kirkwood, J Clin Oncol 14:7, 1996)

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• How melanoma may become resistant to immunotherapy - In the process of immune rejection of tumors, the T-lymphocytes carrying the CD8 cell marker recognize antigens on the tumor cell surface, but only if they are "presented" to them by what are known as the major histocompatibility complex (MHC) class I molecules. MHC class I molecules are composed of alpha- and beta2-chains (beta2- microglobulin). A study from the National Cancer Institute showed how human melanoma cells growing in culture can become unresponsive to immunotherapy by not making beta2-microglobulin. As a result no reactive MHC class I was formed. Since beta2- microglobulin was present in tumor taken from the same patients before immunotherapy, it is likely that their acquired resistance was associated with this change. (Restifo, J National Cancer Institute 88:100, 1996)