Clinical Behavior in Metastatic Brain Disease Is Not Influenced by the Immunological Defense Mediated by CD57 NK-Cells.

Objectives. The purpose of the present study is to verify if the degree of immunological response against metastatic tumors, measured by the number of CD57(+) NK-cells in the tissue of a brain metastasis, influences the later development of new brain metastases or tumor recurrence. Patients and Methods. CD57(+) NK-cells were immunohistochemically identified in the resected tumor, in a series of twenty patients operated on by a single brain metastasis secondary to lung adenocarcinoma. In each case, the degree of CD57(+) NK-cells infiltration within the tumor tissue and the period free of new intracranial disease after brain surgery were recorded. Results. All the studied tumors showed variable number of CD57(+) NK-cells (mean ± standard deviation: 8.4 ± 4.8 per microscopical field, at 200x). The period free of intracranial disease ranged between 10 and 52 weeks (mean ± standard deviation: 22.7 ± 11.9). Statistical analysis showed that there was no correlation between the degree of NK-cells infiltration within the resected tumor and the period free of intracranial disease after surgery (P > 0.05). Conclusion. This finding supports that clinical behavior in metastatic brain disease is not influenced by the immunological response mediated by CD57(+) NK-cells.