Recent findings correlating RACGAP1 expression in various cancer cells with immune cell infiltration suggest a potential role in modulating immune cell dynamics and responsiveness.15 In the context of vaccine-induced immunity, which requires immune cell infiltration to trigger an effective immune response at the site of injection or in proximal lymph nodes, the observed association of RACGAP1 expression-reducing alleles with lower antibody titers suggests that these alleles may weaken immune cell activation or recruitment, potentially dampening vaccine efficacy. This evidence concerns the gene RACGAP1 and cancer.