Circulating C1q-binding macromolecules and their relationship to radiographic characteristics of laryngeal cancer. Circulating macromolecules capable of binding the first component of complement (C1qBM) may represent subcellular components of tissue/tumor debris generated from rapidly proliferating invasive disease. Thirty-eight patients were randomly selected from 74 untreated patients with laryngeal cancer on the basis of disease stage and C1qBM levels. C1qBM levels were correlated with computed tomographic evidence of tumor necrosis and/or thyroid cartilage destruction. Results show that patients with stage III/IV disease with tissue necrosis and/or cartilage invasion had demonstrably higher C1qBM levels than did individuals with similarly staged disease with no evidence of these radiographically defined characteristics (120 +/- 81 micrograms/mL vs 18 +/- 15 micrograms/mL); the strongest association was reflected by the area of necrosis within regional lymph metastases. Elevated C1qBM level in patients with stage III/IV laryngeal cancer thus reflects highly aggressive disease, which is less responsive to therapeutic intervention. 