Vascularity of tumor sections. LLC1 tumors were sectioned and stained using anti-CD31 antibodies. (A) Section from tumor grown in wild type mouse. (B) Section from tumor grown in Egr-1-/- mouse. (C) Results of blinded counting of sections from three wild type (WT) and Egr-1 knockout (KO) tumors, using either the microvascular density method (MVD), i.e., counting all distinct vessels in a high power field, or the Chalkley method, i.e., placing a gridwork over the photograph and counting those vessels that touch the grid, as described . Values shown are averages and standard deviations.