Immunoreactivity of ICAM-1 in human tumors, metastases and normal tissues

Intercellular adhesion molecule-1 (ICAM-1) is implicated to play a role in cancer metastasis, and may serve as a diagnostic tool for tumor prognosis and progression as well as a target for therapeutic intervention. The aim of this study was to carry out a comprehensive survey of ICAM-1 immunoreactivity in normal, malignant and metastatic tissues. We assessed immunoreactivity of ICAM-1 in a total of 300 tissue cores from multiple tissue arrays of normal, malignant, and metastatic tissues by immunohistochemistry. We scored tissue samples for ICAM-1 immunoreactivity on a 0-3 scale, assessed the number of samples exhibiting infiltrating immune cells, and documented ICAM-1 immunoreactivity in some specific cell types. ICAM-1 expression in normal tissues was highest in spleen and absent in the cerebrum, peripheral nerves, pancreas, ovary, breast, uterus, cervix, prostate, lung, larynx, bone marrow, striated muscle, heart, mesothelium, esophagus, small intestine, colon and liver. In primary malignancies, lymphoid tissues received the highest average ICAM-1 score while connective tissue/skin had the lowest average ICAM-1 score. Of the metastatic tissues, those originating from the urinary tract had the highest average ICAM-1 score while those originating from glandular tissues had the lowest average ICAM-1 score. Metastases localized in lymphoid tissues had a higher average ICAM-1 score than those localized in non-lymphoid tissues. Since ICAM-1 is associated with a variety of cancer types and appears to play a role in cancer metastasis, our findings should serve as a helpful resource for investigations of ICAM-1 as a biomarker, as well as a target for therapeutic interventions.