Objective   The current paper aims to investigate the HDAC6 and p21^WAF1 expression, as well as their correlations, in gastric carcinoma and normal mucosa adjacent to carcinoma. The roles of these proteins in gastric carcinoma were also investigated.

  Methods   Immunohistochemistry was performed to detect the HDAC6 and p21^WAF1 expression in 40 specimens of gastric carcinoma, 30 specimens of precancerous lesions (chronic atrophic gastritis with intestinal metaplasia), and 32 specimens of normal mucosa adjacent to carcinoma.

  Results   The expression of HDAC6 in gastric carcinoma, precancerous lesions, and normal mucosa was 65.0%, 43.3%, and 12.5%, respectively. Meanwhile, the positive rates of p21^WAF1 in gastric carcinoma, precancerous lesions, and normal mucosa were 45.0%, 63.3%, and 81.3%, respectively. A significant difference among the expression of HDAC6 and p21^WAF1 in the three groups (P< 0.01) was observed. In gastric carcinoma, the HDAC6 expression significantly increased in stage Ⅲ or Ⅳ tumors (P< 0.05), positive lymph-node metastasis, and poorly differentiated adenocarcinoma (P< 0.05). On the contrary, the p21^WAF1 expression significantly decreased in stage Ⅲ or Ⅳ tumors (P< 0.05), positive lymph-node metastasis, and poorly differentiated adenocarcinoma (P< 0.05). A negative correlation was found between the HDAC6 and p21^WAF1 expression in gastric carcinoma (r= -0.495; P< 0.01) and precancerous lesions (r= -0.451; P< 0.05).

  Conclusion   HDAC6 may have an inhibitory effect on p21^WAF1 and may promote the development, infiltration, and metastasis of gastric carcinoma. HDAC6 and p21^WAF1 are possible molecular markers of gastric cancer and may be used in the diagnosis and prognosis and as therapeutic targets of gastric carcinoma.