CEACAM-7: a predictive marker for rectal cancer recurrence.

BACKGROUND The identification of rectal cancer patients predisposed to developing recurrent disease could allow directed adjuvant therapy to improve outcomes while decreasing unnecessary morbidity. This study evaluates carcinoembryonic antigen cellular adhesion molecule-7 (CEACAM-7) expression in rectal cancer as a predictive recurrence factor. METHODS A single-institution colorectal cancer database and a frozen tissue biobank were queried for rectal cancer patients. CEACAM-7 messenger RNA (mRNA) expression from normal rectal mucosa and rectal cancers was analyzed using quantitative real-time polymerase chain reaction (PCR). Expression-level differences among normal tissue, disease-free survivors, and those that developed recurrence were analyzed. RESULTS Eighty-four patients were included in the study, which consisted of 37 patients with nonrecurrent disease (median follow-up, 170 months), 29 patients with recurrent disease, and 18 patients with stage IV disease. CEACAM-7 expression was decreased 21-fold in rectal cancers compared with normal mucosa (P = .002). The expression levels of CEACAM-7 were relatively decreased in tumors that developed recurrence compared with nonrecurrence, significantly for stage II patients (14-fold relative decrease, P = .002). For stages I-III, disease-free survival segregates were based on relative CEACAM-7 expression values (P = .036), specifically for stage II (P = .018). CONCLUSION CEACAM-7 expression is significantly decreased in rectal cancer. Expression differences between long-term survivors and those with recurrent disease introduce a potential tumor marker to define a subset of patients who benefit most from adjuvant therapy.