To determine whether IFN-γ may be responsible for tumor escape and relapse of neu antigen negative variant (ANV) from primary MMC tumors, WT MMC tumor cells, dnIFN-γ Rα MMC or IFN-γ Rα++ MMC were cultured with IFN-γ (50 ng/106 cells/ml). This evidence concerns the gene ERBB2 and neoplasm.