Expression of beta-catenin in Colorectal Cancer with Liver Metastasis

Han, Sang Ah; Park, Chi Min; Kang, Sin Jae; Song, Sang Yong; Kim, Sang Hee; Son, Dae Soon; Yun, Seong Hyeon; Lee, Woo Yong; Chun, HoKyung

Abstract

PURPOSE: Decreased expression of beta-catenin has been known to be associated with tumor metastasis. However, the clinical relationship between the degree of expression and the prognosis in colorectal cancer (CRC) remains unclear. In this study, we evaluated the prognostic value of beta-catenin expression in CRC patients with liver metastasis.
METHODS
Paraffin embedded blocks were obtained from 70 patients who underwent potentially curative resection for CRC with liver metastasis. Samples from normal colon mucosa, primary CRC and metastatic liver lesion were prepared in tissue microarrays and were stained by immunohistochemistry with monoclonal antibody against beta- catenin. The membranous beta-catenin expression was assessed and the beta-catenin expression difference between primary CRC and metastatic liver lesion was analysed in relation to overall survival as well as disease free survival rates.
RESULTS
In beta-catenin expression, preserved expression (score >6) was observed in 42.0%, and 21.9% of primary CRC tumor samples and tumor samples from metastatic liver lesion respectively. The degree of beta-catenin expression in metastatic liver lesion was significantly lower than that in primary CRC (P=0.022). According to the difference of beta-catenin expression score between primary CRC and liver metastasis, patients were classified as group 'A' and 'B'. Group 'A' was defined as patients showing remarkably decreased expression of beta-catenin in metastatic liver lesion in that the difference of the score was three or more. Group 'B' was defined as patients showing maintained or increased beta-catenin expression in metastatic liver lesion in comparison to primary CRC, in that the difference of beta-catenin expression score was less than three. Overall survival rate and disease free survival rate were significantly better in group 'B' than group 'A' (P=0.02, P=0.002).
CONCLUSIONS
Decreased expression of beta-catenin in metastatic liver lesion may be a poor prognostic marker in colorectal cancers with liver metastasis. A further large-scaled investigation is necessary to define the role of beta-catenin in CRC.