Immune System Marker May Help Diagnose Lung Cancer and Predict Outcomes | Lung Cancer Dispatch |

A recent study found that the complement system, a part of the body's immune response, is activated in lung tumors. Levels of C4d, a breakdown product of the complement system, were elevated in tissue and fluid samples from lung cancer patients. C4d elevation was specific for lung cancer and was not observed in patients with non-cancer lung diseases. More advanced lung cancer was associated with higher C4d levels, but even early-stage lung cancer patients had elevated Cd4 levels. Moreover, higher C4d levels in tumor tissue and blood were associated with shorter survival, even after controlling for cancer stage. C4d blood levels fell after surgical removal of lung tumors. C4d may therefore help diagnose lung cancer, predict outcomes, and monitor response to lung cancer treatment.