Bergers E, van Diest P J, Baak J P
Department of Pathology, Free University Hospital, Amsterdam, The Netherlands.
Anal Cell Pathol. 1995 Jan;8(1):1-13.
DNA-variables such as DNA-ploidy, DNA-index and %S-phase cells have been proven to have prognostic value for breast cancer patients. These variables can be obtained by interpreting DNA-histograms by cell cycle analysis. Since there are a number of potential error sources, the aim of this study was to determine the intra- and inter-observer reproducibility of semi-automated cell cycle analysis with the emphasis on DNA ploidy and %S-phase assessments. The 149 DNA-histograms we used were randomly selected from the Multicentre Morphometric Mammary Carcinoma Project, a nationwide prospective study in The Netherlands on the reproducibility and prognostic power of quantitative assessments. These DNA-histograms were obtained by flow cytometry of fresh frozen breast cancer material. Cell cycle analysis was performed according to a strict protocol with the semi-automated computer program 'MultiCycle', using the background correction option; 68 histograms were analyzed in duplicate by the same observer, and 81 histograms were analyzed by two observers. Assessment of DNA-ploidy showed an intra-observer concordance of 99% (kappa-value 0.98) and an inter-observer concordance of 94% (kappa-value 0.91). The disagreement could be attributed to overlooking a DNA-tetraploid cell cycle in one case, some difficult histograms and varying opinions about small peaks between the observers in a few cases. Intra-observer %S-phase correlation coefficients varied between 0.72 for the %S-phase of the second aneuploid cell cycle and 0.99 for the %S-phase of the diploid cell cycle. Inter-observer correlation coefficients varied between 0.81 for the %S-phase of the second cell cycle and 0.95 for the %S-phase of the diploid cell cycle and the average %S-phase cells. As for DNA-index, intra- and inter-observer correlation coefficients were 0.97 and 0.94, respectively. In conclusion, intra- and inter-observer reproducibility of semi-automated cell cycle analysis of flow cytometric DNA-histograms from fresh breast cancer material using the Multi-Cycle program, following a strict protocol, is in principle high. The results of this study may help us to decide which of the different %S-phases provided by cell cycle analysis software should be used in daily practice.
诸如DNA倍性、DNA指数和S期细胞百分比等DNA变量已被证明对乳腺癌患者具有预后价值。这些变量可以通过细胞周期分析解读DNA直方图来获得。由于存在许多潜在的误差来源，本研究的目的是确定半自动细胞周期分析在观察者内部和观察者之间的可重复性，重点是DNA倍性和S期评估。我们使用的149个DNA直方图是从多中心形态计量乳腺癌项目中随机选取的，该项目是荷兰一项关于定量评估的可重复性和预后能力的全国性前瞻性研究。这些DNA直方图通过对新鲜冷冻乳腺癌材料进行流式细胞术获得。使用半自动计算机程序“MultiCycle”并采用背景校正选项，按照严格方案进行细胞周期分析；68个直方图由同一位观察者重复分析，81个直方图由两位观察者分析。DNA倍性评估显示观察者内部一致性为99%（kappa值0.98），观察者之间一致性为94%（kappa值0.91）。分歧可归因于一例中忽略了DNA四倍体细胞周期、一些难以分析的直方图以及少数情况下观察者对小峰的不同看法。观察者内部S期相关系数在第二个非整倍体细胞周期的S期为0.72，在二倍体细胞周期的S期为0.99之间变化。观察者之间相关系数在第二个细胞周期的S期为0.81，在二倍体细胞周期的S期和平均S期细胞为0.95之间变化。至于DNA指数，观察者内部和观察者之间的相关系数分别为0.97和0.94。总之，按照严格方案，使用Multi-Cycle程序对新鲜乳腺癌材料的流式细胞术DNA直方图进行半自动细胞周期分析，观察者内部和观察者之间的可重复性原则上较高。本研究结果可能有助于我们决定在日常实践中应使用细胞周期分析软件提供的不同S期数据中的哪一个。
