Loss of heterozygosity (LOH) in non-small cell lung cancer: difference between adenocarcinoma and squamous cell carcinoma

Summary Background : In non-small cell lung cancer, a loss of heterozygosity (LOH) is frequently observed; however, few studies have investigated the differences in the LOH status between adenocarcinoma and squamous cell carcinoma. Patients and methods : In a consecutive series of 49 patients with adenocarcinomas and 22 patients with squamous cell carcinomas, the LOH in tumors was analyzed using polymerase chain reaction employing 5 fluorescence-labeled dinucleotide markers (D2S123, D5S107, D10S197, D11SS904, D13S175) and an autosequencer. Results : LOH was more frequently observed in squamous cell carcinoma (20 of 22, 90%) than in adenocarcinomas (33 of 49, 67%) ( P = 0.0348 ), and the number of LOH per patient was also higher in the patients with squamous cell carcinoma (2.2±1.4) than in those with adenocarcinoma (1.5±1.2, P = 0.037 ). In adenocarcinomas, the number of LOH per patients correlated significantly with the pack-year index, whereas the pathological stage significantly affected the number of LOH in squamous cell carcinomas. Conclusion : The presence of LOH is relatively uncommon in adenocarcinoma of the lung; however, the incidence of LOH tends to be associated with the smoking status.