CDX-2 expression is reduced in colorectal carcinomas with solid growth pattern and proximal location, but is largely independent of MSI status.

The homeobox genes are transcription factors that control the development of tissues and organs. In the colon one of such genes is CDX-2. In colorectal carcinomas, the CDX-2 expression is reduced. The aim of the present study was to investigate the presence of CDX-2 in colorectal carcinomas and to relate it to the histological features and microsatellite stability status. The material consisted of 20 carcinomas without microsatellite instability, 19 cases with low microsatellite instability and 19 cases with high microsatellite instability. CDX-2 expression was investigated using immunohistochemistry with CDX2-88 monoclonal antibody and assessed semiquantitatively. In 10 cases no expression of CDX-2 was observed, while in 6 the protein was present in less than 25% of tumor cells. It was noted that reduced expression of CDX-2 was more frequent in carcinomas situated proximally to the splenic flexure (p < 0.015) and in tumors with solid growth pattern (p < 0.03). On the other hand, no significant differences were encountered between groups differing in microsatellite stability. The results suggest that the major factors that determine the presence of CDX-2 in colorectal carcinomas at the protein product level may include cancer location and the solid phenotype of the tumor.