Cdc42-overexpressing mammary glands display abnormal terminal end bud (TEB) morphologies and increased side branching. (A) Representative images of wholemounted mammary glands from 1 week dox-treated line 3, line 4, and control mice. Scale bar = 1000 μm. Graph depicts average number of abnormal TEBs (TEBs with multiple hyperbuds or trifurcations) per gland after 1 week or 3 weeks of dox treatment in lines 3 and 4 compared to dox-treated control mice (1 week n = 9,5,7 P = 0.01,0.07; 3 weeks n = 7,5,4 *P =<0.01). (B) Representative images of whole mounted mammary glands from 5-week dox-treated mice. Scale bar = 1000 μm. Graph depicts average number of branch nodes after 5 weeks of dox treatment in three 4 × 106 μm2 regions of the ductal tree on sides and leading edge of lymph node in number 4 mammary glands (line 3 n = 7,4 *P = 0.005; line 4 n = 8, *P = 0.001; control n = 7).