According to Jia Huafeng and Zhang Deqing, integrin β4 is related to the sensitivity of gefitinib to gastric cancer; they found an obvious negative correlation between p-EGFR and integrin β4, which illustrates the direct interaction between p-EGFR and integrin β4, which contributes to the proliferation and growth of cancers, because gefitinib, a single molecular targeted drug that inhibits EGFRs, is unable to resist the proliferation and growth of tumor cells through upregulating the expression of integrin β4 [100]. This evidence concerns the gene EGFR and gastric cancer.