Contemporary Lung Cancer Screening and the Promise of Blood-Based Biomarkers.

In this issue, the study by Dagnino and colleagues represents an important addition to the maturing field of blood-based biomarkers for lung cancer screening. Their comprehensive approach to analyzing circulating inflammatory proteins identified CDCP1 as a potential biomarker for distinguishing patients with or without lung cancer, a finding that was confirmed in a validation cohort. CDCP1 blood levels, when combined with smoking history, gave an AUC receiver operator characteristic of 0.75. Analysis of transcripts in peripheral blood cells suggested a Wnt/β-catenin signaling-based mechanism for CDCP1 in tumorigenesis providing biologic plausibility. CDCP1 now joins the ranks of other potential blood-based lung cancer screening biomarkers (including epithelial tumor marker proteins, tumor-associated miRNA, antitumor antibodies, and tumor-specific DNA methylation) that need validation in future clinical trials. Further exploration of how CDCP1 levels might be integrated into current lung cancer screening programs, including both detection of lung cancer, and evaluation of the need for invasive biopsies, as well as how CDCP1 performs in different racial populations, is warranted.