ERBB2 and neoplasm: Recently, OVs that were capable of producing BiTE antibodies targeting TAA of CD44 variant 6 (CD44v6), interleukin-12 (IL-12, an immunostimulatory cytokine), and anti-PD-L1 antibodies were developed, while these multifunctional OVs in combination with CAR T cells targeting TAA of HER2 enabled a substantial improvement of disease control in CD44v6 positive tumors with heterogeneity HER2 expression, overcoming multiple resistance mechanisms of tumor antigen loss and inhibitory effect of immune checkpoints which are major obstacles for single immunotherapy in the treatment of solid tumors [144].