Work that first assessed ICAM-1 expression by DTCs was performed by Passlick et al. [226] who found that most NSCLC patients with an ICAM-1−ve tumour had DTCs that remained ICAM-1−ve, while a larger proportion of patients with ICAM-1+ve tumours switched to ICAM−ve DTCs, and that it was the patients with ICAM-1−ve DTCs that tended to have worse outcome. The gene discussed is ICAM1; the disease is neoplasm.