Letter to the editor

In their recent paper, Thomas et al. (1) discussed design, resolution, sensitivity, and reproducibility of the National Aeronautics and Space Administration/American Cancer Society flow cytometer. The results of their study demonstrated high stability and sensitivity of the instrument, which is suitable for detection of near-diploid tumor cells. Although the performance of the instrument is impressive, we believe that Thomas et al. made serious errors in calculating the DNA contents of trout and human. To estimate the DNA content of human cells in picograms of DNA, the authors used trout red blood cell nuclei as the internal reference standard and assumed 2.37 pg of DNA for a trout nucleus. With this value,…