title: Quality control for evaluation of the S-phase fraction by flow cytometry: a multicentric study. The SICCAB Group for Quality Control of Cell Kinetic Determinations.
abstract: Flow cytometric measurement of the S-phase fraction (FCM-S) may be clinically useful in human cancers to identify high-risk patients. However, its clinical application requires a methodologic standardization, a high feasibility, and the reproducibility of results within the same and among different institutions. The interlaboratory quality control program for FCM-S determination (promoted by the Italian Society of Basic and Applied Cell Kinetics) was carried out on DNA diploid and aneuploid cell lines and human breast cancers. FCM-S was quantified by using four mathematical models characterized by different rationales and differences in the degree and shape of background subtraction functions. A satisfactory agreement in FCM-S values among different institutions was observed for cell lines. In human breast cancers, a high reproducibility of FCM-S estimates obtained by the different institutions was observed by using the same model. Conversely, different models gave different FCM-S estimates. Intermodel differences were more evident in aneuploid than in diploid tumors. These findings could explain the contrasting results on the prognostic role of FCM-S in clinically comparable series of breast cancers and should be considered in future efforts to define the optimal and most reproducible mathematical approach to quantify cells in the S-phase.
authors.affiliation: Istituto Nazionale Tumori, Milan, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Silvestrini
mesh_terms: D000782:Aneuploidy; D001943:Breast Neoplasms / Q000235:genetics*; D002458:Cell Fractionation; D004171:Diploidy; D005069:Evaluation Studies as Topic; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007700:Kinetics; D011379:Prognosis; D011786:Quality Control; D015203:Reproducibility of Results; D016196:S Phase / Q000235:genetics*; D014407:Tumor Cells, Cultured