SERUM AUTOANTIBODIES MAY HELP IN EARLY DIAGNOSIS OF LUNG CANCER

Preliminary research has identified autoantibodies—immune proteins found in the blood specific for one's own proteins—that can potentially detect lung cancer early by distinguishing between smokers with or without lung cancer and can also discriminate between lung cancer and low-dose computed tomography (LDCT)–detected noncancerous lung lesions. These findings were published by Wang et al in the Journal of Thoracic Oncology.

The overall 5-year survival of patients with lung cancer is 17%, which is mainly driven by the fact that 57% of lung cancers are diagnosed after the disease has spread, with a 5-year survival of only 4% in this advanced disease setting. If lung cancer is detected in its earliest stage, the 5-year survival jumps to 55%. LDCT is one method to detect lung cancer early in those at high risk, as defined by age and smoking history, and has been shown to reduce mortality by 20%. However, LDCT detects a number of nodules that are in fact not, nor will be, cancerous. Researchers are therefore trying to discover other methods to detect lung cancer early and to distinguish between cancerous and benign LDCT–detected nodules.

Study Findings

Researchers using nucleic acid programmable protein arrays screened 40 early stage lung cancer patients and 40 smoker controls to determine if the former had cancer-specific autoantibodies in their blood that were specific for, and would bind to, any of the proteins in a 10,000 protein panel. They identified 17 potential protein candidates that could discriminate between smokers with or without lung cancer. Then, using the 17 protein panel with enzyme-linked immunoabsorbance assays—a more sensitive test—137 lung cancer patients, 127 smoker controls, and 170 individuals with benign lung nodules were retested for the presence of discriminatory autoantibodies.

The results show that the study identified a classifier of five autoantibodies that can distinguish lung cancer from smoker controls with 30% sensitivity and 89% specificity. They also identified a separate five-autoantibody classifier that could distinguish lung cancer from benign lung nodules with 30% sensitivity and 88% specificity.

The authors commented, “These autoantibodies have the potential to differentiate cancer from LDCT-positive benign disease and therefore warrant further validation in a larger sample set and/or longitudinal samples. These autoantibodies, either individually or as part of a panel, could potentially be a member of companion molecular diagnostic modalities that will benefit patients undergoing LDCT screening for lung cancer.”