<qa>  What is the biological correlate of response?VIII. Determine the biologic correlates of response, including levels of interferon gamma production, natural killer cell activity, infiltration of skin lesions by CD8-positive cells, lymphocyte IL-12 receptor expression, signal transducers and activators of transcription protein levels and IL-12 signal transduction, and induction of apoptosis in tumor cells in the skin of patients treated with this regimen. 