CD4+ T cells promote cytotoxic T lymphocyte (CTL)-mediated anticancer immune 
responses. We have recently identified ideal tumor-associated antigen 
(TAA)-derived long peptides (LPs) that elicit not only TAA-specific TH1 
response, but also CTLs, through cross-presentation. The LP-specific TH1 cell 
responses were augmented in cancer patients vaccinated with CTL epitopes. Our 
findings support the clinical application of LP-based immunotherapy.