Overall, the 3D models of HER2-OE BC immune microenvironment described in this work hold the potential to be used for interrogation of short-to-medium term effects of anti-HER2 therapies on the local immune response, capturing the initial phase of response to anti-HER2 therapies before the onset of immunosuppression, namely in the modulation of NK cell phenotype and in myeloid cell populations. The gene discussed is ERBB2; the disease is breast cancer.