Recently, Cho (2019) showed triple-negative breast cell populations identified by three subtyping marker genes (ERBB2 also known as HER2, ESR1 and PG), while immune landscape cell populations, consisting of subclasses of both tumour and non-tumour (immune) cells, were shaped by distinctive gene expression signatures inferred from copy number alterations within the tumour microenvironment by Chung et al. (2017). Here, ESR1 is linked to neoplasm.