title: Idiopathic pulmonary fibrosis will increase the risk of lung cancer.
abstract: OBJECTIVE
  To review the studies investigating the increased risk of lung cancer in patients with idiopathic pulmonary fibrosis (IPF).
  
  
  METHODS
  Data cited in this review were obtained mainly from PubMed and Medline from 1999 to 2013 and highly regarded older publications were also included.
  
  
  METHODS
  We identified, retrieved and reviewed the information on the frequency, risk factors, anatomical features, histological types, clinical manifestations, computed tomography findings and underlying mechanisms of lung cancer in IPF patients.
  
  
  RESULTS
  The prevalence rates of lung cancer in patients with IPF (4.8% to 48%) are much higher than patients without IPF (2.0% to 6.4%). The risk factors for lung cancer in IPF include smoking, male gender, and age. Lung cancers often occur in the peripheral lung zones where fibrotic changes are predominant. Adenocarcinoma and squamous cell carcinoma are the most common types of lung cancer in patients with IPF. Radiologic features of these patients include peripherally located, ill-defined mass mimicking air-space disease. The underlying mechanisms of the development of lung cancer in patients with IPF have not been fully understood, but may include the inflammatory response, epithelial injury and/or abnormalities, aberrant fibroblast proliferation, epigenetic and genetic changes, reduced cell-to-cell communication, and activation of specific signaling pathways.
  
  
  CONCLUSIONS
  These findings suggest that IPF is associated with increased lung cancer risk. It is necessary to raise the awareness of lung cancer risk in IPF patients among physicians and patients.
authors.affiliation: Department of Respiratory and Critical Care Medicine, the Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, China.
authors.forename: Junyao
authors.initials: J
authors.lastname: Li
authors.affiliation: Centre for Asthma and Respiratory Disease, School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, 2230, Australia.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Pediatrics, the Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Respiratory and Critical Care Medicine, the Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, China.
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Su
authors.affiliation: Department of Respiratory and Critical Care Medicine, the Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.affiliation: Department of Respiratory and Critical Care Medicine, the Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, China. Email: doctorzhangj@sina.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000367:Age Factors; D005260:Female; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000150:complications* / Q000453:epidemiology* / Q000235:genetics; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology* / Q000235:genetics; D008297:Male; D012307:Risk Factors; D012737:Sex Factors