Manjunath Y, et al. - Researchers examined non-small cell lung cancer (NSCLC) patients and high-risk screening subjects having no or benign nodules in a screening low-dose CT (LDCT) for the presence of circulating tumor cell (CTC) clusters (≥2 CTCs in aggregate). On analyzing peripheral blood collected from treatment-naïve NSCLC patients, LDCT screening subjects (55–80 years, ≥30 pack-year smoking history) with no (Lung-RADS 1) or benign lung nodules (Lung-RADS 2), and healthy never-smoking controls, they identified CTC clusters in 12/29 (41.4%) of all NSCLC patients, but not in 31 high-risk screening subjects with Lung-RADS 1 or Lung-RADS 2. Screening subjects had no detectable CTC clusters but could have non-clustered CTCs. CTC clusters are suggested to be a useful and specific liquid biomarker that may assist in screening by LDCT and risk stratification of NSCLC patients.