The presence of aneuploidy or high proliferative activity in cytologic specimens is considered as complementary for the diagnosis of malignancy. To evaluate the diagnostic usefulness of DNA ploidy and cell cycle analysis in lung cancer, we compared the diagnostic yielding rates of DNA ploidy test by brushing specimens using flow cytometry with bronchoscopic forceps biopsy and brushing cytology.

Of the seventy-six cases, 55 cases proved to have malignant diseases(squamous cell cancer: 27, adenocarcinorna: 7, large cell cancer: 1, undifferentiated: 4 and small cell cancer: 16). The incidence of aneuploidy in lung cancer..patients was 32.y %(18/55), as opposed to no cases in benign disease. And the proportion of high proliferative activity(S+GEM>22%) in lung cancer patients was 42.9% (15/35), but none in benign diseases. In (iffy-six of 75 cases(74.7%), cytology of brushing specimens and DNA analysis(either aneuploidy or high proliferative activity vs. diploidy and low proliferative activity) were in concordance. The sensitivity with only brushing cytology was 41.8%(23/55), but with the addition of DNA analysis, it was increased to 56.4%(31/55), without decreasing the specificity(100%). And there was a case whose clue for malignancy was absent except aneuploidy, and he was confirmed to have squamous cell cancer following open thoracotomy There were no differences in the frequency of aneuploidy or high proliferative activity between histologic subtypes of bronchogenic malignancy.

The diagnostic detection rate of lung cancer was improved with the addition of DNA ploidy and cell cycle analysis, and the presence of aneuploidy or high proliferative activity was a relatively specific indicator of malignant disease. It would be useful to test DNA ploidy and cell cycle analysis with brushing specimen for the diagnosis of bronchogenic malignancy particularly in patients whose biopsy specimen could not be obtainable.