Performance of trained classifiers in the 3,273-tumor independent validation cohort. (A) Forest plots of concordance statistics for histopathologic evaluation in the training set (blue square markers), and single-gene classifiers (SGCs; gold circles) and multigene classifiers (MGCs; gray diamonds) in the validation cohort, which plots overall agreement with 95% CIs, specific agreements (positive and negative agreements for estrogen receptor [ER], progesterone receptor [PgR], human epidermal growth factor receptor 2 [HER2], and Ki67) and Nottingham histologic grade (NHG) category agreements (grade [G] 1, G2, and G3), and κ values with 95% CIs. Overall agreement is defined as the number of concordant determinations (assigned to the same class) divided by the total sample size. Positive, negative, and G1/G2/G3 agreements are the proportions of agreement specific to the given category (Data Supplement). (B) Overall agreement of classifiers from the literature compared with our SGCs and MGCs. SCAN-B, Sweden Cancerome Analysis Network—Breast.