Expression of maspin in colon cancers: its relationship with p53 expression and microvessel density

We studied the expression of maspin in colonic adenocarcinoma compared with adenoma and metastatic adenocarcinoma as well as the relationship with its possible regulator, p53. The colonic specimens consisted of 24 adenomas, 49 adenocarcinomas, and 17 metastatic adenocarcinomas. Immunohistochemical staining of paraffin sections was done with microwave-based antigen retrieval methods. The Ki-67 index and the microvessel density were counted using an image analysis system. Maspin expression was positive in 75.5% of adenocarcinomas and 91.7% of adenomas. Only 47.1% of the nodal metastasis showed positive maspin expression. In colonic adenocarcinomas, p53 expression was positive in 44.7% of the maspin-positive groups compared with 100% of the maspin-negative groups (P < 0.005). Colonic adenocarcinomas with the positive maspin expression groups showed less intense microvessel density (181.1 +/- 54.2) than those of the negative maspin expression groups (256.1 +/- 75.4,P < 0.001). In conclusion, we demonstrated maspin expression in colon cancer with a sequential decreased expression rate from adenoma to metastatic carcinomas, which signifies the tumor suppressive function of maspin, and an inverse correlation with p53 and microvessel density, which indicates the regulatory effect of p53 on maspin and anti-angiogenesis effect of maspin.