Moreover, transgenic expression of the cagA gene in p53-null zebrafish induced intestinal small-cell carcinoma and adenocarcinoma.161 These results collectively suggest a key role of tyrosine phosphorylation in the in vivo pathobiological/oncogenic activity of the CagA protein, which may cooperate with alterations of cancer-associated genes in host cells. This evidence concerns the gene TP53 and cancer.