Stable expression of sulfatases in MDA-MB-231 cells inhibits in vivo tumor xenograft growth. A) Average tumor volume at day 35 study endpoint for control vector transfected MDA-MB-231 cells compared with hSulf1 and hSulf2 transfected (S1+S2), hSulf1 (S1), and hSulf2 (S2) transfected cells. The average value and standard deviation are based on caliper measurements and calculated tumor volumes from the eight mice in each group *p < 0.03. B) Average mitotic index at day 35 study endpoint for hSulf1 (S1) and hSulf2 (S2) transfected tumors in comparison to control as determined by Ki-67 staining *p < 0.001. C) Representative fields used for quantification of mitotic index by Ki-67 staining. The scale bar represents 50 μm..