title: Correction of modal DNA values obtained by microspectrophotometry and tests for their shifts.
abstract: The technical problems in the application of statistical analyses of the nuclear DNA contents measured by plug or two-wavelength Feulgen microspectrophotometry were discussed. The skewness of the nuclear DNA content unimodally distributed in a cluster could be corrected by logarithmic transformation. A mean value of the logarithmically transformed DNA contents was a more logical characterization of cancer than a graphically obtained mode of nontransformed values. Equations were derived to estimate the number of cells in the G1- and S-phases of mitotic cycles contained within the cluster and to estimate the correction factor of the mean of transformed values of cells in the G1-phase. Thus statistical tests for a shift in the nuclear DNA content of the cells in question in the G1-phase from that of control cells were made possible.
mesh_terms: D002453:Cell Cycle; D004273:DNA, Neoplasm / Q000032:analysis*; D006801:Humans; D008433:Mathematics; D009369:Neoplasms / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods*
chemical_list: D004273:DNA, Neoplasm