Co-expression of oncogenic HER2/NEU and the CRE recombinase from the NIC transgene in the mammary epithelium resulted in deletion of floxed capns1 alleles and ablation of CAPNS1 expression in mammary tumors arising in NIC capns1flox/flox (KO) mice, while tumors from NIC capns1+/+ (WT) mice retained CAPNS1 expression (Supplementary Figure 1). The gene discussed is CAPNS1; the disease is breast cancer.