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

Abstract

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.

Keywords: ICAM-1; immunohistochemistry; metastasis; tissue array; tumor.

Figure 1

ICAM-1 immunoreactivity patterns in various normal tissue, tumor, and metastases samples. (A) Normal human tonsil treated with Rabbit IgG as negative control; (B) Normal human tonsil stained for ICAM-1 as positive control. Numbers in parentheses indicate ICAM-1 score of the tissue: (C - H) Normal human tissues expressing ICAM-1: C) Normal human testes (1+); D) Normal human thyroid (1+); E) Normal human cerebellum (2+); F) Normal human parathyroid (2+); G) Normal human pituitary (2+); H) Normal human colon (0). (I - L) Examples of various staining patterns seen in tumors and metastases: I) Adenocarcinoma of small intestine (3+); J) Metastatic squamous cell carcinoma from larynx found in lymph node (3+); K) Infiltrating ductal carcinoma of breast (2+). Arrows show perinuclear staining; L) Adenocarcinoma of prostate (2+). Arrow shows infiltrating cells positive for ICAM-1. (M - P) Examples of tumors with ICAM-1 scores 0-3: M) Metastatic squamous cell carcinoma in fibrous tissue from larynx found in the neck (0−); N) Adenocarcinoma of pancreas (1+); O) Metastatic adenocarcinoma from rectum found in liver (2+); P) Retinoblastoma (3+). All images were taken at 40×.

Figure 2

Average ICAM-1 scores and proportion of samples with ICAM-1 positive immune cell infiltrate in various tumor categories for primary (A-B) and metastatic (C-D) malignancies.