ESR1 and breast cancer: The neoepitope load is highly correlated with the mutational burden in all the breast cancer samples considered together (R2 = 0.86, p < 0.001; Fig. 3a), or when broken up by subtypes (Additional file 5: Figure S3): ER/PR(+)HER-2(−) (R2 = 0.90, p < 0.001), HER-2(+) (R2 = 0.86, p < 0.001), and TNBC (R2 = 0.84, p < 0.001).