On-going phase I studies include assessment of the HER2-directed vaccine TAEK-VAC-HerBy in combination with HER2-antibodies of immune checkpoint inhibitors in advanced solid tumours (NCT04660929), and a separate study assessing a peptide vaccine, which induces humoral immunity against HER2-expressing tumour cells, will provide further data on the clinical utility of immunotherapeutic vaccines in gastric cancers (NCT01417546) [86] (Table 2). This evidence concerns the gene ERBB2 and gastric cancer.