Decreased expression of p12^DOC-1 is associated with more advanced tumor invasion in human gastric cancer tissues

Background/Aims: p12^DOC-1 is a well-known growth suppressor; however, its role in gastric carcinogenesis is still unclear. We investigated the expression of p12^DOC-1 in gastric cancer tissues and its possible correlation with p53 expression, and determined its clinical significance. Methods: Immunohistochemical staining using the tissue array method was performed on 180 human gastric carcinomas. The clinicopathological features and prognostic significance were analyzed. Results: Of the 180 tissue samples, p53 expression was positive in 85 (47.2%) and p12^DOC-1 expression was negative in 140 (77.8%). The negative expression of p12^DOC-1 was significantly associated with a more advanced depth of tumor invasion and stage (p < 0.05). No apparent correlation was found between p12^DOC-1 and p53 expressions. The 5-year survival rate of the p12^DOC-1-positive cases (53.7%) was higher than that of the p12^DOC-1-negative cases (39.3%); however, neither p12^DOC-1 nor p53 expression status had any statistically significant prognostic value. Multivariate analysis revealed that lymph node metastasis, distant metastasis, lymphatic invasion and perineural invasion were independent prognostic factors. Conclusions: This is the first report that suggests that p12^DOC-1 may be involved in the development and progression of gastric cancer. Further studies are required to clarify its exact role in the mechanism of gastric carcinogenesis.