Fig. 1.

β1-Integrin deletion delays tumor onset. (A) Schematic representation of the MMTV/activated erbB2 transgenic mice (NIC strain) and of the β1-integrin^flox allele. (B) Kaplan-Meier analysis of tumor onsets. Control NIC β1^wt/wt mice versus NIC β1^f/wt versus NIC β1^f/f (P = 0.0004). Median tumor onset values are indicated. The P values were calculated from a two-tailed Student t test. (C) β1-Integrin expression in the mammary breast tumor was assessed for NIC β1^wt/wt or NIC β1^f/f mice by immunoblotting.