• Carla Verri, Luca Roz, Davide Conte, Triantafillos Liloglou, Anna Livio, Aurelien Vesin, Alessandra Fabbri, Francesca Andriani, Christian Brambilla, Luca Tavecchio, Giuseppe Calarco, Elisa Calabrò, Andrea Mancini, Diego Tosi, Paolo Bossi, John K Field, Elisabeth Brambilla, Gabriella Sozzi, and EUELC Consortium.
• Department of Experimental Oncology, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy.
• Am. J. Respir. Crit. Care Med. 2009 Mar 1; 179 (5): 396-401.

RationaleFragile histidine triad (FHIT) is a tumor suppressor gene involved in the pathogenesis of lung cancer.ObjectivesThe purpose of this study was to investigate the different molecular alterations leading to the inactivation of FHIT gene function and to validate their use as biomarkers of risk for progression of the disease in patients belonging to the multicentric European study for the Early detection of Lung Cancer (EUELC) who were resected for early-stage lung tumors.MethodsFHIT immunostaining was performed on 305 tumor samples. The methylation status of FHIT promoter was assessed by nested methylation-specific polymerase chain reaction (MSP-PCR) in 232 tumor and 225 normal lung samples of which a subset of 187 patients had available normal/tumor DNA pairs. Loss of heterozygosity (LOH) at the FHIT locus was analyzed in 202 informative cases by D3S1300 and D3S1234 microsatellite markers.Measurements And Main ResultsLost or reduced FHIT expression was found in 36.7 and 75.7% of the tumor samples, respectively. Methylation of the FHIT promoter was found in 36.7% of tumor and 32.7% of normal lung samples, whereas LOH was detected in 61.9% of the tumors. A strong association with complete loss of FHIT expression was present when methylation and LOH were analyzed together (P = 0.0064). Loss of FHIT protein expression was significantly more frequent in squamous cell carcinoma histotype (P < 0.0001) and in smokers (P = 0.008). FHIT methylation in normal lung was associated with an increased risk of progressive disease (OR, 2.27; P = 0.0415).ConclusionsOur results indicate that different molecular mechanisms interplay to inactivate FHIT expression and support the proposition that FHIT methylation in normal lung tissue could represent a prognostic marker for progressive disease.

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