OBJECTIVE To examine the possibility of human sodium iodide symporter （hNIS） protein expression in lung cancer cells. METHODS Human lung A549 cancer cells were thawed and cultured in vitro. The cells were divided into an experimental group transfected with a recombinant pcDNA3-hNIS plasmid and a control group transfected only with a pcDNA3 plasmid. The recombinant plasmid vector encoding the hNIS gene （pcDNA3-hNIS） was amplified, purified and identified. The hNIS gene was followed by DNA sequencing. A Western blot and an immunohistochemical assay were applied to detect the hNIS protein expression in the transfected human lung A549 cancer cells. RESULTS Restriction enzyme digestion and DNA sequencing results showed the size and direction of the inserted gene in the recombinant pcD- NA3-hNIS plasmid was correct. The Western blot method and immunohistochemical analysis showed a positive NIS protein expression in the experimental group. The NIS protein was detected mainly in the cell membranes showing a positive rate up to 70.6% with no expression of the NIS protein in the control group. There was a significant difference between two groups （P=0.000）. CONCLUSION The hNIS gene was transfected effectively into human lung A549 cancer cells mediated by Lipofectamine 2000, and was expressed with its protein in vitro.
Objective： To observe the relationship between non-small cell lung cancer with neuroendrocrine differentiation （NSCLC-NE） and patients＇ postoperative survival. Methods： During April 1997 to April 1999, 98 cases of hlng cancer were surgically treated. The tumor specimens of the patients were stained by NE markers, i.e. neuron specific enolase （NSE） and synaptophysin （SY）. The intensity of NE markers reaction was divided as ＂＋＂. ＂＋＋＂. ＂＋＋＋＂ scale groups. The same specimens were also examined under an electron microscope for the specific neuroendocrine granules. All enrolled patients were followed up for 36 months, and the longest follow-up time was 60 months. The COX proportional hazard model multivariate analysis was applied to observe the relationship between the NSCLE-NE and the patients＇ postoperative survival. Results： In 91 cases of NSCLC, 63.7% （58/91） were positive for NE stain reaction. Among them, 59.3% （54/91） were positive for NSE and 24.1% （22/91） for SY. 48.4% （44/91） were considered as NSCLC-NE by the combination of NE inarker stain reaction and electron microscopic examination. COX proportional hazard model lnnltivariate analysis showed that the NSCLC-NE patients＇ survival was significantly shortened （P=0.048）. The following factors were related to NSCLC-NE patients＇ survival： lung cancer cell differentiation （P=0.006）, clinical lung cancer stage （P=0.001）, the NE markers reaction （P=0.054）. Conclusion： NSCLE-NE is significantly related to the cancer cell differentiation and the patients＇ postoperative survival. The NE markers should be applied clinically as one of prognostic factors to evaluate the postoperative survival of NSCLC patients.
