To the Editor.
—Dr Rosenberg and colleagues1 report 5 years of experience in treating patients with metastatic melanoma or renal cell cancer with interleukin-2. The poor clinical results that they achieved over that time (7% success rate compared with the spontaneous success rate of 5%) may be caused by an error in the model design on which their protocols were based. In their model experiments with immunogenic mouse tumors,2 treatment of the tumor-bearing mice with interleukin-2 and tumor-infiltrating lymphocyte cells began 3 days after transplanting the tumor into the syngeneic host. They used the phrase "established pulmonary micrometastases" to describe the characteristics of the system, implying that 3 days after transplantation, the tumors had acquired the in vivo characteristics of an autochthonous tumor.These authors have overlooked reports from my laboratory that were published in 1977 that showed that immunogenic mouse tumor cells became "killer cell" resistant by
Manson LA. Treatment of Metastatic Melanoma and Renal Cell Carcinoma With Interleukin-2. JAMA. 1994;272(17):1327. doi:10.1001/jama.1994.03520170037027