Background Activated leukocyte cell adhesion molecule (ALCAM/CD166) is a member of the immunoglobulin superfamily that contributes to cell migration. The present study investigated the potential role of ALCAM in the transition from normal endometrium to endometrioid adenocarcinoma (EEC).

Methods To clarify the role of ALCAM in endometrial tumorigenesis, we determined the levels of protein and messenger RNA expression of ALCAM in human endometrial tissue (proliferative phase [n = 20], secretory phase [n = 20], simple hyperplasia [n = 15], complex hyperplasia [n = 12], atypical hyperplasia [AH, n = 14], EEC [n = 42]) using immunohistochemistry, Western blot, and semiquantitative reverse transcription-polymerase chain reaction, respectively.

Results Expression of ALCAM detected by immunohistochemistry showed a gradual increase from normal endometrium to atypical hyperplasia in a membranous pattern; in addition, cytoplasmic staining emerged in a few cases of simple hyperplasia and complex hyperplasia, which also showed an increasing tendency. Most cases of EEC showed a homogenously strong staining in all parts of the tumor; other cases showed either membranous or cytoplasmic strong staining; heterogeneous loss of membranous staining was also found in some cases. Similar results of ALCAM expression were detected by reverse transcription-polymerase chain reaction and Western blot. In EEC, ALCAM expression was significantly increased in high-grade tumors and cases with myometrial invasion; however, no correlation was found between ALCAM expression and surgical pathological stages.

Conclusions The up-regulation of ALCAM expression during endometrial carcinogenesis and the correlations of ALCAM expression with grade and myometrial invasion suggest its potential role as a diagnostic and prognostic biomarker.