Fig. 4
Lapatinib exposure impedes mammary morphogenesis and suppresses cell proliferation. a Mammary gland whole mounts were prepared from 24-week-old mice of control and lapatinib (100 mg/kg/day for 8 weeks)-treated groups. Representative images are shown at 7.5x and 30x magnification. The average number of side branches per 10 mm2 is graphed as the mean ± S.E. in the right panel (** p < 0.01). b Control and lapatinib (100 mg/kg/day for 8 weeks)-treated mice were injected with BrdU 90 min before euthanization at 24 weeks of age and then were prepared for IHC analysis of BrdU nuclear incorporation. BrdU-positive cells are indicated by brown staining. c TUNEL staining of apoptotic cells is indicated by brown staining in mammary gland tissues from 24-week-old vehicle and lapatinib-treated mice. BrdU-positive and TUNEL-positive cell percentages are graphed as the means ± S.E. (** p < 0.01)