ESR1 and breast cancer: In a study of 254 ER+/HER2– BC cases, Haralick texture (homogeneity, entropy, contrast, dissimilarity, energy) and Ashman’s D indicators were computed for Ki67, ER, and PR using systematic hexagonal grid subsampling of DIA data.14 Among them, Ki67 Haralick texture entropy, which quantifies variability in Ki67 expression across grid elements, serves as an indicator of spatial heterogeneity of biomarker expression.