This model was used to identify immune gene-enriched tumors in arm A and arms B and C. Immune gene enrichment was linked to increased RFS in arms B and C ( HR , 0.35 ; 95 % CI , 0.22 to 0.55 ; P < .001 ) , whereas arm B and C patients who did not exhibit immune gene enrichment did not benefit from trastuzumab ( HR , 0.89 ; 95 % CI , 0.62 to 1.28 ; P = .53 ) .