Loss of heterozygosity at 3p in non-small cell lung cancer and its prognostic implication

We examined 110 patients with non-small cell lung cancer who underwent consecutive pulmonary resection for loss of heterozygosity (LOH) at the short arm of chromosome 3 (3p). We performed a PCR-based microsatellite polymorphism analysis for detection of LOH. The microsatellite markers used were D3S966 (3p21.3), D3S1007 (3p21. 3-22), and D3S1228 (3p14.1-14.3). Of 98 informative cases, 3p LOH was found in 45 (46%). 3p LOH was more prevalent in squamous cell carcinoma (24/35, 69%) than in adenocarcinoma (18/52, 35%; P = 0.0019). There was no significant association between 3p LOH and sex, disease stage, or grade of differentiation. However, patients with 3p LOH tended to survive for a shorter period of time (P = 0.0631, log rank test). There was no such tendency in squamous cell carcinoma (P = 0.7513), but in adenocarcinoma, the difference of survival was significant (P = 0.0015). Cox's proportional hazards model also predicted that 3p LOH was an independent poor prognostic marker in adenocarcinoma (P = 0.0502) but not in squamous cell carcinoma or in the entire cohort (P = 0.7866 and 0.1371, respectively). LOH at 3p may help to identify non-small cell lung cancer patients with a poor prognosis, who thus need an intensive postoperative follow-up protocol or who are suitable for novel investigational therapeutic approaches. It is also suggested that the putative tumor suppressor gene at 3p may have a different role in squamous cell carcinoma and adenocarcinoma of the lung.