E Impact of ESRP1 knockdown on in vivo tumor growth. Five million cells (2-control, 2C3, 9-control and 9C2) were implanted into mammary fat pads of athymic mice (five mice per group) in the presence of supplemental estrogen. Tumors were measured weekly using calipers for external measurements. Tumor volume was calculated as L x W2/2, where L is length and W is width (note the different scale for tumor volumes). Data (mean ± SD) were calculated using two-way ANOVA (n= 5 mice per group). 