RESUMEN
<p><b>OBJECTIVE</b>To investigate DNA aneuploid and P16 expression in biopsy specimens from lung cancer, and to study genetic instability and the application of flow cytometry in lung cancer pernicious degree diagnosis.</p><p><b>METHODS</b>Blood cells and cancer cells in biopsy specimens were marked simultaneously with anti-CD45 and anti-P16 fluorescent antibody, and the ratio of CD45+ P16+ cells and CD4- P16+ cells was compared. DNA content in biopsy specimens from lung cancer was detected by flow cytometry.</p><p><b>RESULTS</b>Among the 74 cases of lung cancer, there are 46 cases of DNA aneuploid (62.2%). Thirty-seven cases of lung cancer expressed P16 lowly (50%). Twelve cases of lung cancer only expressed P16 lowly (16.22%), 21 cases of lung cancer only expressed DNA aneuploid (28.38%), and 25 cases not only expressed P16 lowly but also expressed DNA aneuploid (33.78%). Indexes of malign degree, such as P16 low expression or DNA aneuploid could be detected in 58 cases among the 74 cases (78.38%) by flow cytometry.</p><p><b>CONCLUSION</b>P16 low expression and DNA aneuploid are the indexes of lung cancer malign degree, and flow cytometry can be used to study genetic instability and evaluate biopsy specimens from lung cancer.</p>