The T50 in MMTV-neu in the absence of Timp3 was ~76 weeks compared with ~31 weeks in Timp3+/+; MMTV-neu (calculated from Kaplan-Meier curve of the age at first detection of tumor) (Jackson et al., 2015), suggesting that Timp3−/−MMTV-neu might be another suitable model for studying aging-related breast cancer progression. The gene discussed is ERBB2; the disease is breast cancer.