We also find that the cytoplasmic tail of GPIbα regulates the tumor cell‐induced platelet protein kinase C‐α (PKCα) activation, and both the pharmacological inhibition and genetic ablation of platelet PKCα attenuate tumor cell‐induced platelet activation, tumor cell–platelet interaction, tumor cell migration and invasion, and metastasis. This evidence concerns the gene GP1BA and neoplasm.