Cellular heterogeneity of DNA/total‐protein content in human lung tumors, as determined by flow cytometry

With the aim of distinguishing neoplastic cell sub‐populations of different prognostic and diagnostic significance, dual‐parameter measurements (DNA/protein) have been simultaneously determined in a (256, 256) channel matrix in lung samples derived from 110 patients affected by neoplastic and non‐neoplastic lung diseases. Biparametric analysis demonstrated that cells with abnormally high red fluorescence (i.e., protein content), which is indicative of unbalanced growth, were often observed in malignant tumors as compared with normal lung samples. Furthermore, the dual‐parameter analysis allowed recognition of additional aneuploid tumor‐cell lines, indicating that the frequency of cytometrically determined diploid tumor is lower than that previously described by DNA monoparametric analysis. The recognition of aneuploid sub‐populations by dual‐parameter analysis in clinically and histologically negative one‐parameter flow‐cytometric “diploid” samples assumes important diagnostic value. The results have also shown the presence of multiple protein sub‐populations in clones with the same ploidy value, indicating a higher level of cellular heterogeneity than demonstrated by DNA monoparametric measurements.