In the mice bearing tumors from the MHC-I negative GR9-B11 tumor cell clone, a strong immunostimulation was produced, with no detection of overt metastases during follow-up; however, overt metastases appeared after these animals were depleted of CD8+ T lymphocytes, indicating that the immune response mediated by CD8+ T lymphocytes kept the metastases in a permanent dormant state (17). This evidence concerns the gene CD8A and neoplasm.