Human MOB1 Expression in Non–Small-Cell Lung Cancer

Purpose Human MOB1 ( hMOB1 ) is a recently isolated gene that is a human homologue of the Schizosaccharomyces mitotic checkpoint gene MOB1 . The loss of checkpoint control in mammalian cells results in genomic instability, leading to the amplification, rearrangement, or loss of chromosomes, events associated with tumor progression. We hypothesized that hMOB1 might be expressed in non–small-cell lung cancer (NSCLC). Patients and Methods We attempted to determine the influence of hMOB1 expression on clinicopathologic features in patients with NSCLC who had undergone surgery. Expression of hMOB1 messenger RNA (mRNA) was evaluated by reverse transcription-polymerase chain reaction in 60 NSCLCs and adjacent histologic normal lung samples using LightCycler®. Results Human MOB1/glyseraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA expression was significantly decreased in the tumor of lung cancer tissue (3.347 ± 4.306) compared with normal lung tissue (4.833 ± 4.306; P = 0.0437), although 22 of 60 lung cancer tissue samples had > 1 tumor-normal ratio of MOB1/GAPDH mRNA expression. There was no relationship between hMOB1 gene expression and age, sex, pathologic stages, or pN status. However, decreased hMOB1/GAPDH expression was especially seen in pT1 lung cancer (tumor-normal ratio; 0.318 ± 0.328) when compared with pT4 lung cancer (1.915 ± 1.895; P = 0.0362). Conclusion The decreased expression of hMOB1 mRNA might be the early phase phenomenon for tumor invasion from NSCLC. Alternatively, loss of mitotic checkpoint might play a role in oncogenesis for lung cancer.