Expression of CEACAM-1 in pulmonary adenocarcinomas and their metastases

CEACAM-1 is involved in intercellular adhesion and is expressed in a variety of human tissues. In cases of malignant transformation, a down-regulation or loss of CEACAM-1 has been shown. In contrast, CEACAM-1 is not expressed in normal lung tissue or melanocytes. It has been demonstrated that an expression in these tissues is associated with the development of metastatic disease. The aim of the present investigation was to analyze a possible association between the expression of CEACAM-1 in pulmonary adenocarcinomas and their lymph node and hematogenous metastatic cells.

CEACAM-1 expression was immunhistochemically evaluated in primary tumors, lymph nodes and distant metastases of 96 patients with metastatic pulmonary adenocarcinoma who had undergone surgery between 1999 and 2002.

Expression of CEACAM-1 was shown in 78 out of 96 primary tumors (81.3%). A significant positive correlation was found between CEACAM-1 expression on cells of the primary tumor, lymph node metastases (p < 0.005) and hematogenous metastases (p = 0.03). CEACAM-1 expression did not correlate with stage, gender, grading or patients' age. Compared to patients with tumors not expressing CEACAM-1, patients with a CEACAM-1-expressing tumor had a shorter median overall survival (21 vs. 28 months) and progression-free survival (11.7 vs. 16.3 months).

CEACAM-1 is expressed in most primary pulmonary adenocarcinomas. This investigation demonstrates that its expression is preserved in lymph node and hematogenous metastases, indicating that its expression is of functional significance for both metastatic sites. These results support the prognostic relevance of the expression of CEACAM-1 in pulmonary adenocarcinoma.