Association of Levels of Circulating C1q Binding Macromolecules with Induction Chemotherapy Response in Head and Neck Cancer Patients

Ninety-five untreated patients with squamous cell carcinoma of the upper aerodigestive tract expressed significantly higher levels of Clq-binding macromolecules as compared to 45 noncancer-bearing controls. No relationship between Clq-binding macromolecules and levels of circulating IgG-immune complexes as determined by the solid-phase Clq-binding assay or the C3d-solid-phase assay could be defined suggesting that Clq-binding macromolecules were distinct from IgG-circulating immune complexes. An elevated level of Clq-binding macromolecules within these patients was predictive of subsequent response to induction chemotherapy; those with elevated levels characteristically showed no response. Using multivariate logistic regression analysis including the covariates of American Joint Committee staging parameters as well as Clq assay results, levels of the isolated macromolecules added significant prognostic information as to the probability of chemotherapeutic response. The quantitation of Clq macromolecules has clinical implication as to choice of therapeutic regimens against head and neck cancer. The nature of these substances remains to be defined.