Tissue microarrays in Chinese human rectal cancer: study of expressions of the tumor-associated genes.

Backgrounds/aims: The cellular basis for rectal cancer development is still unclear. The aim of this study was to evaluate the relationship between the expression of p53, cyclinD1, bcl-2, ß-catenin, c-myc, cyclooxygenase-2 (COX-2) and nm23-H1 and the clinicopathological characteristics of rectal cancer.

Methodology: Expressions of p53, cyclinD1, bcl-2, ß-catenin, c-myc, COX-2 and nm23-H1 proteins were detected by immunohistochemical staining to two tissue microarrays containing tissues accumulated from 54 human rectal cancers and 40 para-cancer mucosa.

Results: Significant differences were demonstrated between the rectal cancers and their benign para-cancer counterparts according to the expressions of p53, cyclinD1, bcl-2, ß-catenin, c-myc, COX-2 and nm23-H1 (p<0.05). Additionally, positive correlations of ß-catenin with cyclinD1 and c-myc (r=0.412, p=0.002; r=0.447, p=0.000) and of p53 with bcl-2 (r=0.332, p=0.001) were found. Cancer tissues with overexpression of ß-catenin or bcl-2 were less likely to differentiate to advanced grade. Expression of cyclinD1 had a correlation with clinical stages (p=0.039). In addition, a negative correlation was found between nm23-H1 expression and the histological grades, distance metastasis and Duke's stages.

Conclusions: Aberrant expression of p53, cyclinD1, bcl-2, ß-catenin, c-myc, COX-2 and nm23-H1 might attribute to the carcinogenesis of human rectal cancer. Furthermore, cyclinD1 and nm23-H1 might be involved in rectal cancer progression. This study recommends the application of tissue microarrays in rectal cancer research for its reliable quick throughput.