Similarly, this DCB subtype specificity also extends to lung cancer: 4 of the 6 lung DCB genes (CXCL17, SFTA3, SFTPA2, and SLC34A2) were upregulated in the plasma of patients with lung adenocarcinoma compared to those with squamous cell carcinoma (Fig. 4d). The gene discussed is SFTPA2; the disease is lung cancer.