Schönfeld et al. generated a stable NK92 cell line expressing a humanized anti-HER2 CAR containing CD28 and CD3ζ signaling domains and these CAR NK cells efficiently lysed HER2+ tumor cells in vitro and the specific recognition of tumor cells resulted in selective enrichment of anti-HER2 CAR NK-92 cells in orthotopic breast carcinoma xenografts and reduction of pulmonary metastasis in a RCC model, respectively (189). Here, CD28 is linked to neoplasm.