Again, in contrast with HER2− tumours, ESR1 expression was significantly correlated with the change in Ki67 (r = − 0.61, p = 2.57E−03) being among the 25 genes whose baseline expression correlated with better Ki67 response (Additional file 5: Figure S3c; Additional file 2: Table S16). This evidence concerns the gene ERBB2 and neoplasm.