This concept is further highlighted in luminal A tumors, for example, where regions of dysfunctional T cells with expression of immune checkpoint inhibitors, e.g., PDL-1, are depleted compared to other regions within the tumor (intratumoral heterogeneity); and compared to other subtypes (intertumoral heterogeneity) where areas rich in T regulatory lymphocytes and proliferating cells are abundant, for example, in ER-tumors (Danenberg et al., 2022). This evidence concerns the gene CD274 and neoplasm.