ERBB2 and adenocarcinoma: Here, we observe that serum sHER2 concentrations detected by ELISA are higher in a subset of primary NSCLC patients with adenocarcinoma (adjusted for age, 60% of men and 30% of women had sHER2 concentrations above the 95th cut-off threshold for healthy controls), suggesting that sHER2 may warrant investigation as a theragnostic biomarker to select a subset of patients with lung adenocarcinoma for treatment with HER2-targeted drugs.