Table I.
Functions and methylation prevalences of selected genes in lung adenocarcinoma
| Gene | Location | Functions of encoded proteins | Methylation in lung ADC |
| p16 | 9p21 | Cyclin-dependent kinase inhibitor that blocks cell cycle progression | 31–98 (12,16,17) |
| RASSF1A | 3p21.3 | Modulates apoptotic and cell cycle checkpoint pathways | 47–69 (12,16,17) |
| MGMT | 10q26 | DNA repair enzyme | 30–51 (18,19) |
| Reprimo | 2q23.3 | Involved in the p53-induced G2 cell cycle arrest | 32–33 (20,21) |
| TNFRSF10C | 8p22–p21 | A TNF receptor family member that modulates apoptosis | 12 (22) |
| TNFRSF10D | 8p21 | A TNF receptor family member that modulates apoptosis | 15 (22) |
| CHFR | 12q24.33 | Mitotic checkpoint protein that delays transition to metaphase | 10–19 (23–25) |
| BOLL | 2q33 | RNA-binding protein regulating meiotic G2/M transition | NR |
| TSLC1 | 11q23.2 | Intercellular adhesion molecule | 46 (26) |
| TUBB4 | 19p13.3 | A major component of microtubules | NR |
| PCDH10 | 4q28.3 | A-cadherin family gene involved in cell–cell adhesion | NR |
| MMP2 | 16q13–q21 | Degrades extracellular matrix | NR |
| GPNMB | 7p15 | A transmembrane protein suppressing growth and metastasis | NR |
| ICAM5 | 19p13.2 | A member of the intercellular adhesion molecule | NR |
| JPH3 | 16q24.3 | A junctional protein between plasma membrane and ER | NR |
| SFRP1 | 8p12–11.1 | Antagonist of the transmembrane frizzled receptor that is component of the Wnt signaling | 34–76 (17,27) |
| SFRP2 | 4q31.3 | Antagonist of the transmembrane frizzled receptor that is component of the Wnt signaling | 52–84 (17,27) |
| APC2 | 19p13.3 | Depletes the beta-catenin pool and inhibits Wnt signaling | NR |
| GNB4 | 3q26.32–33 | A guanine nucleotide-binding protein that integrate signals between receptors and effector proteins | NR |
| SULF2 | 20q12–13.2 | Heparin sulfate 6-O-endosulfatases that selectively remove 6-O-sulfate groups from heparin sulfate | NR |
| IGFBP3 | 7p13–p12 | A carrier of IGFs that negatively regulates IGF-1 bioavailability | 62–76 (28,29) |
| DAB2IP | 9q33.1–33.3 | Cytosolic adapter protein for LDL endocytosis and also suppresses mitogenic activity of Ras | 37 (30) |
| AK5 | 1p31 | Synthesis of adenine nucleotides for cellular metabolism | NR |
| XT3 | 3p21.3 | Transport of hydrophilic solutes across cell membrane | NR |
| BHLHB4 | 20q13.33 | Basic helix-loop-helix-containing transcriptional regulator | NR |
| BHLHB5 | 8q13 | Inhibitor of a neuronal differentiation gene BETA2 | NR |
APC, adenomatosis polyposis coli; ER, endoplasmic reticulum; IGF, insulin-like growth; LDL, low density lipoprotein; NR, no report of DNA methylation in lung adenocarcinoma or lung cancer in general. TNF, tumor necrosis factor.