Table II.

The identified smoking-associated 7-gene signature.

Gene symbol	Gene title	Molecular function (Gene Ontology)
ABCA3	ATP-binding cassette, sub-family A (ABC1), member 3	ATP, nucleotide binding; ATPase, transporter activity
CRTAC1	Cartilage acidic protein 1	Calcium ion binding
CYP3A4	Cytochrome P450, family 3, subfamily A, polypeptide 4	Monooxygenase, electron carrier, oxidoreductase activity; heme, metal ion and steroid binding
GPRC5C	G protein-coupled receptor, family C, group 5, member C	Receptor activity; protein binding
LTF	Lactotransferrin	Ferric iron, heparin, metal ion, protein binding; peptidase, serine-type endopeptidase activity
PIGN	Phosphatidylinositol glycan anchor biosynthesis, class N	Phosphotransferase, transferase activity
SEMA3C	Sema domain, immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin) 3C	Receptor activity; semaphorin receptor binding