On the one hand, the authors postulate the possibility that immune stimulation results from modifications of lysozyme on the membrane of tumor cells, as previously suggested by Warren [37] and Osserman [38], causing recognition of altered cells by lymphocytes; on the other hand, similar stimulation of lymphocytes against tumor cells is also observed when treatment with HEWL occurred before the implantation of the tumors, clearly indicating a modulatory effect of the immune system independent of an effect on the surface of the tumor cells. The gene discussed is LYZ; the disease is neoplasm.