In addition, Bao et al. [51] indicated an inverse correlation between HER2 and miR-139 expression in gastric cancer; the interaction between HER2 and CD44-enhanced histone deacetylation in the miR-139 promoter region upregulates CXCR4 expression, leading to gastric tumor progression and subsequently metastasis. The gene discussed is CXCR4; the disease is gastric neoplasm.