How strong is the association between IPF and lung cancer? An answer from airway's DNA

Idiopathic pulmonary fibrosis is a chronic progressive disease of lung interstitium of unknown etiology with poor prognosis. In patients with IPF, the incidence of lung cancer is much higher than that in the general population. The identification of noninvasive biomarkers for early diagnosis of IPF is of great relevance in consideration of the management of these patients. Among the noninvasive omic markers, an increasing interest has been directed toward the study of genetic alterations of microsatellites (MAs) in exhaled breath condensate (EBC). The aim of this preliminary study was to investigate the MAs, located in chromosomal regions 8p21.3-q11.1 and 17q11.2-q21, that harbor tumor suppressor genes, in EBC and in the paired whole blood (WB) of IPF patients. Eleven IPF patients were compared with 10 healthy control subjects. All subjects underwent collection of the EBC and WB. The EBC was collected using a condenser. Four microsatellite markers (THRA1, D17S579, D17S250 and D8S137) were used for the analysis of MAs. The EBC-DNA and WB-DNA were amplified by PCR; PCR products were analyzed using the ABI Prism 310 DNA. Microsatellite alterations were found in 58.82 % of EBC-DNA and 12.50 % of WB-DNA in patients with IPF (p < 0.01). None of the healthy subjects exhibited MAs in the studied markers. Our findings suggest that these genetic alterations, studied in EBC, may play an important role in the complex genetic basis of IPF. Since these MAs are frequently detected in cancer, they might explain the higher relative risk of tumorigenesis in this disease.