Once a primary breast tumor was detected by palpation in experimental MMTV-PyMT; HK2f/f; UBC-CreERT2 mice and control MMTV-PyMT;HK2f/f mice, the mice were injected with tamoxifen for 7 consecutive days to systemically delete HK2 in the experimental MMTV-PyMT;HK2f/f;UBC-CreERT2 mice (Fig. 6b). The gene discussed is HK2; the disease is breast neoplasm.