In a separate series of experiments, SK-BR-3 cells (a Her2-positive cell line) were used to determine whether there was anti-Her2 antibody produced in the Lkb1−/−/NIC mice that were used as a model of spontaneous breast tumor development (19) in which we had previously demonstrated a reduced level of tumor development in the context of ranitidine treatment (10). This evidence concerns the gene ERBB2 and breast neoplasm.