CDX2 Is a Prognostic Biomarker for Unresectable Metastatic Colorectal Cancer

Colorectal cancer (CRC) with reduced expression of the homeobox transcription factor CDX2, a master gene essential for the development and maintenance of the intestinal tract, is known as a poor prognosis subtype of CRC. The recurrence rate is high in patients with CDX2^low CRC. However, the prognostic significance of CDX2 in advanced CRC is unclear. This study aimed to elucidate the prognostic significance of CDX2 in unresectable metastatic CRC (mCRC).

Twenty-nine patients with unresectable mCRC who underwent primary site resection at the Kobe University Hospital during a 6-year period from January 2008 to January 2015 were included. The tissues from those patients were immunohistochemically stained with anti-CDX2 antibody (clone: CDX2-88). The patients were divided into CDX2^high CRC group and CDX2^low CRC group and their prognoses were analyzed.

There were no clear differences in background between the two groups. A low CDX2 expression was associated with reduced overall survival (37.67 months vs. 25.32 months, p=0.03) and tended to associate with reduced progression-free survival (17.4 months vs. 12.9 months, p=0.37). Two patients received chemotherapy after resection of the primary lesion and obtained pathological complete response.

CDX2 expression might be a possible prognostic biomarker for unresectable mCRC.