CD4 and neoplasm: In addition, tumor-associated peptide epitopes, such as those derived from patients’ neoantigens identified by exome sequencing and in vitro T cell reactivity screening, could be applied in vaccine formulations (18, 19) to activate the patient’s peripheral CD4+ Th cell repertoire or to expand and support in vivo maintenance of adoptively transferred T cells reactive against these MHC II–presented peptides (Figure 1).