Expression of R-cadherin on Lin^-HSCs. Flow cytometry was used to analyze cell surface expression of R-cadherin on (1) vascular targeting Lin^- HSCs; (2) nontargeting Lin⁺ HSCs; or (3) nontargeting CD31-/CD34-/Mac1-HSCs. Ten percent of Lin^- HSCs were labeled by preimmune control goat IgG, while 80% were labeled by goat anti-R-cadherin antibodies. Nontargeting subpopulations of HSCs contain significantly fewer cells positive for R-cadherin expression.