Clinical relevance of ICAM-1 expression in primary lesions and serum of patients with malignant melanoma. 
Immunohistochemical staining with monoclonal antibodies detected ICAM-1 in about 69% of 55 primary melanoma lesions and in about 89% of 28 metastatic lesions.  The average number of melanoma cells stained by anti-ICAM-1 monoclonal antibodies was approximately 65% in both primary and metastatic lesions.  ICAM-1 expression in primary lesions was significantly associated with their thickness.  Furthermore, ICAM-1 expression in primary lesions was associated with a reduction in the disease-free interval and with survival.  At variance with the information in the literature, the association with clinical parameters of the disease did not reach the level of statistical significance.  This discrepancy is likely to reflect the inclusion in the present study of a small number of primary lesions with a thickness < 1.5 mm.  At variance with recently published data, the level of serum ICAM-1 in 75 patients with malignant melanoma was found to be nonsignificantly different from that in 47 age- and sex-matched controls.  The level of serum ICAM-1 was significantly increased only in patients with stage III melanoma with lesions and in those with stage IV melanoma.  Two novel and clinically relevant findings of the present investigation are (a) the significantly higher serum ICAM-1 level in patients with liver metastases than in those with metastases in other anatomic sites and (b) the progressive increase of ICAM-1 level in serial blood samples from patients with disease progression.  The latter findings suggest that monitoring of serum ICAM-1 level may represent a valuable noninvasive indicator system to detect liver metastases and to monitor the clinical course of the disease in patients with malignant melanoma.