Influence of systematic errors on the evaluation of the S phase portions from DNA distributions of solid tumors as shown for 328 breast carcinomas

Optimizing flow cytometric DNA ploidy and S-phase fraction as independent prognostic markers for node-negative breast cancer specimens

Developing a reliable and quantitative assessment of the potential virulence of a malignancy has been a long-standing goal in clinical cytometry. DNA histogram analysis provides valuable information on the cycling activity of a tumor population through S-phase estimates; it also identifies nondiploid populations, a possible indicator of genetic instability and subsequent predisposition to metastasis. Because of conflicting studies in the literature, the clinical relevance of both of these potential prognostic markers has been questioned for the management of breast cancer patients. The purposes of this study are to present a set of 10 adjustments derived from a single large study that optimizes the prognostic strength of both DNA ploidy and S-phase and to test the validity of this approach on two other large multicenter studies. Ten adjustments to both DNA ploidy and S-phase were developed from a single node-negative breast cancer database from Baylor College (n = 961 cases). Seven of the adjustments were used to reclassify histograms into low-risk and high-risk ploidy patterns based on aneuploid fraction and DNA index optimum thresholds resulting in prognostic P values changing from little (P < 0.02) or no significance to P < 0.000005. Other databases from Sweden (n = 210 cases) and France (n = 220 cases) demonstrated similar improvement of DNA ploidy prognostic significance, P < 0.02 to P < 0.0009 and P < 0.12 to P < 0.002, respectively. Three other adjustments were applied to diploid and aneuploid S-phases. These adjustments eliminated a spurious correlation between DNA ploidy and S-phase and enabled them to combine independently into a powerful prognostic model capable of stratifying patients into low, intermediate, and high-risk groups (P < 0.000005). When the Baylor prognostic model was applied to the Sweden and French databases, similar significant patient stratifications were observed (P < 0.0003 and P < 0.00001, respectively). The successful transference of the Baylor prognostic model to other studies suggests that the proposed adjustments may play an important role in standardizing this test and provide valuable prognostic information to those involved in the management of breast cancer patients.

Flow cytometric DNA analysis and p53 protein expression show a good correlation with histologic findings in patients with Barrett's esophagus

BACKGROUND

There is a considerable degree of subjectivity and, therefore, substantial interobserver and intraobserver disagreement in the diagnosis and grading of dysplastic lesions in Barrett's esophagus (BE). The aim of this study was to evaluate the usefulness of DNA flow cytometry and immunohistochemical staining for p53 protein as objective methods to complement the conventional histologic diagnosis of dysplasia in patients with this disease. The most common problems and the possible advantages of using these procedures are analyzed briefly in this article.

METHODS

Formalin fixed, paraffin embedded tissue from 55 patients diagnosed with BE were processed for flow cytometric measurements (ploidy and proliferation index) and p53 immunostaining.

RESULTS

Both the cytometric data and the positivity of staining for p53 revealed a statistically significant increase throughout the following sequence: no dysplasia --> indefinite for dysplasia --> low grade dysplasia --> high grade dysplasia --> adenocarcinoma. There was also a highly significant correlation between the results of the cytometric study and the positivity of staining for p53.

CONCLUSIONS

In the future, the use of this procedure could play an important role in the evaluation of patients with BE. Considering that staining for p53 is technically simple, economical, and quick, and the materials required are available to most pathology laboratories, this method appears to be a firm candidate for application as a biomarker in BE. The authors have shown that it is possible to obtain adequate results for cytometric analysis with small formalin fixed, paraffin embedded biopsies if a strict protocol for the acceptance of tissue samples and/or histograms is observed.

Cellular kinetics in rectal cancer

Measurements of dynamic tumour cell kinetic parameters, particularly the potential doubling time (Tpot) may have potential as predictive assays for treatment outcome after radiotherapy. This paper details the distributions of Tpot and other kinetic and DNA content parameters measured in rectal cancers. Biopsies were taken from 119 patients approximately 6 h after infusion of 200 mg m-2 bromodeoxyuridine (BrdUrd). The samples were analysed by bivariate DNA/BrdUrd flow cytometry. The primary purpose of the study was to measure the kinetic parameters of labelling index (LI), duration of S-phase (TS) and Tpot. Secondarily, tumour DNA ploidy (DNA index) and S-phase fractions (SPFs) were also estimated from the univariate DNA histograms. The 101 evaluable patients were classified according to clinical stage as T2 (n = 12), T3 (n = 53), T4 (n = 28) or recurrent tumours (n = 8). Of the evaluable tumours, 73 were DNA aneuploid. The median LI, TS, and Tpot of the aneuploid tumours were 21%, 20 h and 3.3 days respectively. The calculated LI, TS, and Tpot of diploid tumours were subject to uncertainties because of the contribution of normal cells. The LI and SPF of all tumours were, however, significantly (P < 0.001) correlated, having a correlation coefficient of only 0.76. The wide distributions of values for LI (quartiles 13.5%, 26.9%) and Tpot (quartiles 2.4, 5.6 days) that were found are necessary baseline information if these parameters are to be useful in individual treatment selection or as predictors of treatment outcome.

Debris compensation of DNA histograms and its effect on S-phase analysis

Debris compensation is an important variable affecting S-phase fraction (SPF) analysis in flow cytometric DNA histograms. The SPF was estimated in fresh frozen breast carcinomas using the following four debris subtraction algorithms: modeling debris as an exponential curve (EXP); the incorporation of nuclei cut a single time into the exponential moel (EXP-SC); the random cutting of nuclei into multiple pieces of varying sizes (MC); and a combination of both nuclear cutting models (SC-MC). Comparison of SPF estimates indicated that the various debris subtraction models yielded differences in SPF, with SPF values obtained using the exponential model having considerable variation compared to SPF estimates from histograms where debris was modeled by algorithms based on nuclear slicing and fragmentation. However, SPF estimates could be affected by initial placement of the nuclear debris boundaries, the coefficient of variation of the G0/1 peak, and the relative amount of debris. Using the ratio of the height of the G0/1 peak to the height of the debris between the chicken red blood cells (CRBC) and G0/1 peaks as an objective measurement of nuclear debris, debris compensation was necessary in diploid DNA histograms where this ratio was as low as 1.5%. Taken in the context of SPF prognostic cutoff levels, variation in debris models and boundaries can change the classification of cases with borderline SPF levels into the poor prognostic high SPF categories, thereby making the comparison of SPF values derived from different studies difficult.

FDG uptake, tumor proliferation and expression of glycolysis associated genes in animal tumor models

To determine the influence of tumor cell proliferation and changes in the genetic program in malignant cells on the fluorodeoxyglucose (FDG) uptake we performed PET studies in several animal tumors: spontaneous mammary fibroadenoma, chemically-induced mammary adenocarcinoma and Dunning prostate adenocarcinoma. The expression of the glucose transporter (GLUT1) and of hexokinase (Hk) was measured using 32P-labeled cDNA probes and densitometry. Furthermore the proliferative activity was determined with one-dimensional flow cytometry. The FDG uptake and the proliferation parameters were not correlated. The normalized amounts of GLUT and Hk mRNA were lower in spontaneous fibroadenomas and prostate tumors than in chemically induced mammary. The FDG uptake was correlated to GLUT1 expression with r = 0.83 and to Hk expression with r = 0.77. Multiple regression analysis revealed a relation of FDG uptake to GLUT1 and HK with r = 0.87. Our results show that the FDG uptake in our study was related not to differences in proliferation, but rather to differences in the transcription of glycolysis associated genes.

Prospective study correlating P120 antigen expression with established prognostic factors in breast cancer

P120 is a nucleolar proliferation antigen found in rapidly dividing cells and a variety of malignancies. Previous retrospective studies have demonstrated that, when detected in human breast cancer, P120 is associated with a poorer prognosis. To determine whether P120 expression correlates with other prognostic factors in breast cancer, we prospectively analysed pathologic and clinical data from 61 patients. P120 was detected in 40 of the 61 specimens (66%). No significant correlation existed between P120 expression and either tumour size or hormone receptors. A significant correlation was found between P120 expression and histological grade, degree of aneuploidy, S-phase fraction, degree of nodal involvement, and stage of disease. P120 is a biological marker indicative of tumour aggressiveness and may play an important role in determining which patients would most benefit from adjuvant therapy.

DNA Cytometry Consensus Conference. Consensus review of the clinical utility of DNA cytometry in carcinoma of the breast

This is the consensus statement regarding the clinical utility of DNA cytometry in breast cancer from the DNA Cytometry Consensus Conference held in Prout's Neck, Maine, USA, on October 1-4, 1992. Guidelines for clinical DNA cytometry generated at that meeting also appear in this issue of Breast Cancer Research and Treatment.

Clinical significance of DNA ploidy and S-phase fraction and their relation to p53 protein, c-erbB-2 protein and HCG in operable muscle-invasive bladder cancer

DNA ploidy and S-phase fraction (SPF), determined by flow cytometry were studied in 118 patients with muscle-invasive transitional cell carcinoma (TCC) of the urinary bladder, scheduled for cystectomy after pre-operative radiotherapy (20 Gy/1 week) with or without systemic cisplatin-based neo-adjuvant chemotherapy. The correlation between these parameters and immunohistochemically demonstrated p53, c-erbB-2 and HCG was also investigated. There were 16 DNA diploid and 102 DNA non-diploid tumours. DNA ploidy was not related to the T (all 118 patients) or pN (58 patients) category, occurrence of stage reduction or cancer-related 5 years survival. Patients with high SPF tumours tended, however, to have a better prognosis than those with low SPF TCC reaching the level of significance (P < 0.05) for those patients who had high SPF tumours and received neo-adjuvant chemotherapy. Fifty-one of the tumours were p53 positive. p53 positive tumours were significantly more often found in TCC with low SPFs than in those with high SPFs. Respectively 12 and 9% of the tumours were HCG and c-erbB-2 positive, without correlation to DNA ploidy or SPF. We conclude that DNA ploidy does not represent a prognostic parameter in muscle-invasive operable bladder carcinomas. A high SPF, determined by FCM, may be helpful to identify patients with chemotherapy-sensitive TCC of the urinary bladder.

Improved DNA content histograms from formalin-fixed, paraffin-embedded liver tissue by proteinase K digestion

An improved method for the enzymatic digestion of formalin-fixed, paraffin-embedded liver tissue for DNA content analysis by flow cytometry is presented. Forty samples of histologically normal liver were alternately digested by the traditional pepsin method or a new method utilizing proteinase K and heat. Sixteen (40%) of the pepsin-digested samples had apparent DNA aneuploid peaks by flow cytometry. False DNA aneuploid peaks were not present in any of the histograms obtained after proteinase K digestion. Microscopy showed that the pepsin-digested samples had residual cytoplasmic remnants which contained fluorescent material. Samples digested with proteinase K had few cytoplasmic remnants. The average G0/G1 coefficient of variation after proteinase K treatment was lower (41%) and the fluorescent intensity higher (128%) than the pepsin-treated samples. The apparent mean S-phase (a combination of S-phase cells and underlying debris) after proteinase K digestion was 35% of the pepsin-treated samples. Primary and secondary tumors of the liver that were DNA aneuploid after pepsin treatment were also DNA aneuploid after proteinase K treatment. A modified digestion protocol utilizing proteinase K and heat can provide superior results for DNA content analysis of formalin-fixed, paraffin-embedded liver tissue.

Comparison of PCNA/cyclin immunohistochemistry with flow cytometric S-phase fraction in breast cancer

Kinetic index determined by enumeration of neoplastic cells positive for proliferative cell nuclear antigen (PCNA) in 70 breast carcinomas (avidin-biotin immunoperoxidase technique) was compared to synthesis-phase fraction (S-phase, or SPF) values obtained by flow cytometry (FCM) using a multiparametric, 2 color method (dual-label propidium iodide/cytokeratin-FITC). The percent PCNA positive tumor cells (12.5% mean, range 1-28%) was significantly greater in aneuploid tumors (14.2% mean, N = 35) compared to diploid range tumors (10.7% mean, N = 35) (p less than 0.05), and was correlated with SPF derived from ungated DNA histograms (12.5% mean +/- 5.5%, r = 0.45, p less than 0.001). Marginally stronger statistical correlations were observed between the PCNA index and SPF values calculated from cytokeratin-gated (15.8% mean, r = 0.53, p less than 0.001) DNA histograms or from SPF values obtained following linear baseline debris subtraction (mean = 8.1%, r = 0.48, p less than 0.001). Significant associations were identified between PCNA index and prognostically important clinicopathologic parameters including nuclear grade (p = 0.014), presence of necrosis (p = 0.005), and angiolymphatic invasion (p = 0.003). We conclude: 1) PCNA index is comparable to FCM SPF and correlates with factors of known prognostic importance in carcinoma of the breast; 2) baseline debris and contaminating events derived from non-epithelial cells both represent significant artifacts in proliferative fraction estimates derived from FCM DNA histograms; and 3) multiparametric analysis may represent one means of improving the specificity and clinical value of FCM SPF determinations.

Prognostic potential of flow cytometric S-phase and ploidy prospectively determined in primary breast carcinomas

In a prospective study of a consecutive breast cancer series accumulated in the period 1978-82, the S-phase fraction (SPF) and ploidy status were determined by flow cytometry performed on cell nuclei derived from samples of 580 primary tumors. Sixty percent of the tumors were non-diploid. After correction for debris the median SPF values were 7.3% overall, 12% for non-diploid tumors, and 2.9% for diploid tumors (2.6% when nodal subsets N2 and N3 and cases with metastases at presentation were excluded). The SPF values correlated both to tumor size (p = 0.008) and to the number of positive axillary lymph nodes (p = 0.03). At clinical follow-up in 1986, 467 unilateral breast cancer patients who had undergone radical treatment for cure could be evaluated with respect to the prognostic value of both the SPF value and ploidy status. The median duration of follow-up was then 59 months (range 2-90), and the median time-to-recurrence 24 months (range 2-69, n = 137). At follow-up in 1991, 201/467 of the patients had died, the median duration of follow-up being 50 months (range 2-126) for the decreased, and 119 (range 6-148) for the survivors. In multivariate analysis (Cox's proportional hazards models), the strongest independent predictors of distant recurrence-free survival (DRFS) were the number of positive axillary lymph nodes (p less than 0.0001), the debris-corrected SPF value alone (p = 0.003, versus p = 0.05 for uncorrected value), and ploidy status combined with the corrected SPF value (p = 0.0002). When age was taken into account, both the corrected SPF value and the ploidy-SPF combination were predictors of crude survival (p = 0.006 and p = 0.002, respectively). In univariate life-table analysis, the 5-year DRFS rate was 93% in node-negative (N0) cases with an SPF less than 7.3%, as compared to 80% in those with an SPF greater than or equal to 7.3% (p = 0.005). Among node-positive cases, the prognostic value of the SPF was confined to those with 1-3 positive nodes, the 5-year DRFS rate being 68% in cases with an SPF less than 7.3%, as compared to 40% in cases with an SPF greater than or equal to 7.3% (p = 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

DNA ploidy, S-phase fraction, and G2 fraction as prognostic determinants in human pancreatic cancer

The DNA ploidy, S-phase fraction (SPF), and G2 fraction of pancreatic cancer tissue was measured by flow cytometry in 95 patients. Forty-nine per cent (n = 47) had a diploid DNA index, and 51% (n = 48) of tumours were aneuploid. Aneuploid tumours and high-grade tumours had significantly higher S-phase and G2-fraction values than diploid tumours or low-grade tumours. Diploid and tetraploid tumours had a more favourable prognosis than non-tetraploid aneuploid tumours (p = 0.0020) during the mean follow-up of 6 years. The type of therapy (p = 0.07), histologic grade (p = 0.06), SPF (p = 0.1), and G2 fraction (p = 0.02) had predictive value in survival analysis as well. In multivariate survival analysis, including flow-cytometric, histologic, and clinical variables, diploidy and tetraploidy had independent predictive value. The results suggest that flow cytometry might be used in grading of pancreatic cancer. Such a grading would have practical value if new modes of therapy are being developed. Forty-one per cent of multiple samples had a heterogeneous DNA index when multiple samples were used. Consequently, flow cytometric analysis of pancreatic cancer using multiple samples is recommended.

Breast cancer proliferation measured on cytological samples: a study by flow cytometry of S-phase fractions and BrdU incorporation

Cell kinetics have been shown to be an important predictor of clinical evolution of operated breast cancer. We established a method for the estimation of the proliferative activity of tumour cells obtained by fine needle sampling without aspiration (FNS), using simultaneously S-phase fractions (SPF) measured on DNA histograms and 5-bromodeoxyuridine (BrdU) labelling index (BLI) measured by flow cytometry. Biparametric BrdU/DNA flow cytometry could be performed in 122 of 189 (65%) consecutive patients. The mean BLI of the cytologically malignant FNS (118) was of 3.0 and the median of 2.2%. One hundred and forty-eight DNA histograms (78%) were suitable for SPF analysis, of which 141 presented malignant cells, showing a mean of 4.5 and a median of 3.5%, comparable to BLIs. These results were obtained from fluorescence peak area histograms with doublet discrimination and background subtraction allowing the measurements of SPFs as low as 0.4%. An excellent correlation was thus observed between BLIs and SPFs, for the 94 cases for which both results were available (r = 0.85). Infrequent discordances (9%) were noted with SPFs considerably higher than BLIs. Seven patients had three consecutive FNS of their tumour at weekly intervals before treatment. Some variability in the proportions of multiple subpopulations of tumour cells was observed on the DNA histograms. In contrast, proliferation indices (SPF or BLI) were reproducible, suggesting homogeneous growth rates. We conclude that an estimation of the proliferative activity of breast tumours at any stage of the disease is possible routinely by SPF and/or BLI analysis of FNS. At least one quantitative proliferation index could be obtained for 91% of patients.

Prognostic importance of cellular DNA content in head-and-neck squamous-cell cancers. A comparison of retrospective and prospective series

Flow cytometric DNA-ploidy measurements were performed on formalin-fixed tumour specimens from 172 patients with squamous-cell cancers (SCCs) of the head and neck region. One hundred and two samples were chosen retrospectively and a further 70 consecutive patients were analysed prospectively in order to assess the prognostic significance of DNA ploidy and DNA index (DI). There were no statistically significant differences between retrospective and prospective groups in regard to age, sex, TNM stage, ploidy or DI. Sixty-seven percent of patients were aneuploid (65% retrospective; 71% prospective). The proportion of aneuploid tumours was significantly higher among poorly differentiated tumours. Survival analysis using Cox multivariate regression modelling revealed that DNA aneuploidy and increasing DI were significant independent prognostic factors for both relapse-free and overall survival. The relapse and death rates among aneuploid subjects were approximately 3 times as high as those for diploid subjects. Patients with a DI greater than 2.11 (hypertetraploidy) experienced a 6.6-fold higher death rate than diploid subjects. These results provide strong support for the incorporation of DNA ploidy profiles into the clinical management of patients with head and neck cancer.

DNA histogram debris theory and compensation

In this paper we describe a theory of DNA histogram debris generation and compensation that can be applied to paraffin-embedded frozen tissue preparations. The theory predicts the distribution of fragments generated from single and multiple random sectioning of three-dimensional ellipsoids representing nuclei. The fragment distribution is assumed to be a major component of the underlying debris in DNA histograms. A comparison of S-phase fractions (SPF) from matched tissue prepared by frozen and formalin-fixed paraffin-embedded DNA methods demonstrates the usefulness of the theory.

Improved prognostic impact of S-phase values from paraffin-embedded breast and prostate carcinomas after correcting for nuclear slicing

Nuclear debris may significantly interfere with the analysis of S-phase fraction (SPF) from paraffin-embedded tumors. We used a background subtraction algorithm to compensate for the effects of slicing of tumor cell nuclei during preparation of paraffin-embedded specimens. DNA histograms were analyzed from 88 node-negative breast and from 78 prostatic carcinomas. Median SPFs corrected for nuclear slicing were lower than uncorrected ones in both breast cancer (7.6% vs. 5.7%) and prostate cancer (6.7% vs. 4.2%). The median SPF value in each group was used as a cut-off point in survival studies. As compared with the uncorrected SPFs, corrected SPF levels resulted in a more significant survival difference between breast cancer patients with above and below median SPF (p = 0.0014 vs. p = 0.014) and in a higher relative risk (RR) of death (4.5 vs. 3.1). The same was true for prostate cancer survival (p less than 0.0001 vs. p = 0.002) and RR (5.3 vs. 3.1). Compared with the exponential background subtraction method, the sliced nuclei correction was more reproducible and could be applied in all evaluable histograms without the risk of overcompensation. In conclusion, our results support the use of background correction with the sliced nuclei model in DNA flow cytometric studies of archival tissues.

Ploidy, proliferative activity and prognosis. DNA flow cytometry of solid tumors

Flow cytometric study has been used to measure the cellular DNA content of solid tumors for the last decade, and of paraffin-embedded tumor specimens for the last 5 years. Ploidy and proliferative activity are the two properties commonly measured by DNA content flow cytometric study. The ability to study archival, paraffin-embedded tumors has hastened an appreciation of the prognostic utility of this assay. Either abnormal ploidy or elevated proliferative activity predict a worsened disease-free or overall survival in most common adult malignancies. Both abnormalities are associated with poor outcome in locoregional breast, non-small cell lung, and colorectal cancers, and in all stages of ovarian cancer. Abnormal ploidy is also a dire prognostic indicator for cancers arising from the kidney, bladder, prostate, and endometrium. Clinical management of patients with these diseases may be aided by studying their tumors for these objective markers of biological aggressiveness.

Rapid in vitro bromodeoxyuridine labeling method for monitoring of therapy response in solid human tumors

In vitro bromodeoxyuridine (BrdUrd) incubated single-cell suspensions obtained from solid tumors were fixed on slides for subsequent sample processing. As dispersal of nuclei largely was avoided, only small amounts of cells were needed for examination. The sensitivity of detecting even low BrdUrd incorporation rates could be improved by treatment with intense DNA denaturation conditions. This technique was applied to monitor cytokinetic response to chemotherapy and radiation in oral carcinomas by analysing biopsies taken consecutively in the course of treatment. By combining BrdUrd labeling and DNA flow cytometry, cells arrested in S phase easily could be distinguished from cells showing continuous proliferation.

Effect of sonication on paraffin-embedded tissue preparation for DNA flow cytometry

Since the publication of paraffin block extraction procedures, flow cytometric analysis of DNA ploidy and S-phase of tumor specimens has been widely applied. DNA aneuploidy, DNA tetraploid (elevated G2/M), and elevated S-phase are clinically significant in some tumor systems. True DNA tetraploid cell lines will contain a large 4c population and perhaps an 8c population; samples with cell aggregates will also contain a 6c population. Microscopic examination of samples having a 6c peak revealed nuclei with adhering debris and doublets, triplets, and larger nuclear aggregates. After sonication, a uniform suspension of single nuclei without adherent debris was seen. In addition to reducing the percent of G2/M cells, sonication also reduced S-phase percent such that it was closer to the bromodeoxyuridine labeling index. The DNA ploidy classification of specimens was also compared pre- and post-sonication. Four of 96 breast cancer samples changed classification; all were specimens in which the histogram became cleaner and a small DNA aneuploid peak became apparent after sonication.

Flow cytometric analysis of DNA content and keratins by using CK7, CK8, CK18, CK19, and KL1 monoclonal antibodies in benign and malignant human breast tumors

We have used a double-labelling flow cytometry analysis of keratin (CK) and DNA in breast cancer. Five monoclonal anti-keratin antibodies were tested: KL1 recognizing Mr 55,000-57,000 keratins, and "anti-glandular epithelia," LE41, RGE-53, and LP2K specific for CK n. 7, 8, 18, and 19 of Moll's classification, respectively. Flow cytometric (DNA-CK) analysis was performed on 10 benign and 19 malignant human breast tumors. All the benign tumors were diploid and 63% of the malignant tumors were aneuploid. This technique permits the analysis of DNA in the epithelial fraction alone. In aneuploid tumors, gating the DNA-keratin-positive population allowed accurate DNA analysis without interference due to debris background and non-epithelial cells. Moreover, double-labelling using the CK19 antibody gave a better identification of near-diploid tumors. An enhancement of keratin expression in malignant tumors was observed with CK 19 (P less than 0.001), KL1 (P less than 0.01), CK 8 (P less than 0.05), and CK18 (n.s.) compared to benign tumors. The comparison of keratin expression in aneuploid and diploid malignant tumors revealed reduced CK8, CK18, and CK19 in the former.

Flow cytometric measurements of DNA and other cell components in human tumors: a critical appraisal

Fundamental principles of flow cytometry with emphasis on DNA measurements and cell cycle analysis in human cells and tissues are summarized. Some of the pitfalls of cell preparation techniques and histogram interpretation are discussed at length. While consensus has been reached for some organs and tumors that DNA quantitation by flow cytometry (or image cytometry) may be of prognostic value, for most cancers studied to date the information remains incomplete. Thoroughly lacking are well-structured prospective studies because retrospective studies, while suggestive, may not necessarily be of the same value. Potential usefulness of other tumor markers is briefly discussed. Many fundamental questions concerning definitions of "diploid" and "aneuploid" tumors have not been satisfactorily settled. While the goal of "objective measurements" is worthy of further pursuit, the interpretation of results is often highly subjective. The biologic reasons for behavioral differences between diploid and aneuploid tumors are still totally obscure.

DNA flow cytometry, clinical and morphological parameters as prognostic factors for advanced malignant and borderline ovarian tumors

Patients with malignant ovarian (n = 111) and borderline (n = 8) tumors (FIGO stage III/IV) underwent surgery and chemotherapy and were analyzed clinically (age, residual tumor after surgery) and morphologically (type, grade, psammoma body content), and by means of flow cytometry (DNA ploidy, S-phase fraction). Follow-up was 12-72 months for investigation of survival. Patients under 60 years of age (n = 18) with malignant tumors showed longer survival than patients over 60 (n = 93) (P = 0.078). Residual tumor was relevant for prognosis in malignant tumors only if macroscopically there was no residual disease (n = 13). There were no significant differences between residual tumors less than or equal to 2 cm (n = 61) and greater than 2 cm (n = 37). WHO typing was of little importance for survival analysis. Compared to borderline tumors (n = 8), serous (n = 65), endometrioid (n = 13), nonclassifiable (n = 12), mucinous carcinomas (n = 8), and nonepithelial tumors (n = 12) had a poor prognosis. Psammoma bodies were found in 25 patients with serous carcinomas, 7 of them had a high content. The prognosis for these 7 patients was much better than that for patients with a moderate or low psammoma body content (P = 0.006). Twenty-three epithelial tumors were graded G1, 28 were G2, and 47 were G3. However, grading was considered only as a prognostic factor in serous carcinomas (n = 65) (P = 0.028). A total of 199 DNA histograms from 119 patients were analyzed by flow cytometry (FCM). There were no correlations between tumor type and DNA ploidy or S-phase fraction. Seven of eight borderline tumor and all serous carcinomas with a high content of psammoma bodies were diploid combined with a low (less than or equal to 4%) S-phase fraction. DNA ploidy and S-phase fraction were excellent prognosticators. Of 99 epithelial malignant tumors, 35 were diploid and 64 were aneuploid. An S-phase fraction less than or equal to 4% was found in 39 patients, 4.1-10% in 73 patients, and greater than 10% in 23 patients. Diploid tumors and tumors with a low S-phase fraction showed the best survival (P = 0.007, resp. 0.0001). Our study emphasizes the importance of an accurate histology, including information on psammoma body content, and the importance of DNA flow cytometry. The advantage of FCM is that the results are simple, reproducible, and objective.

Cell proliferation kinetics in human solid tumors: relation to probability of metastatic dissemination and long-term survival

A large number of studies have investigated the relationship between the long-term survival and the percentage of tumor cells in S phase assessed by autoradiography after tritiated thymidine labelling, image cytometry, flow cytometry or labelling with an halogenated analog of thymidine, in various types of human solid tumors. The survey of the results clearly shows that the S-phase fraction (SPF) is of high prognostic significance in several types of cancers, in particular in breast cancers, non-Hodgkin lymphomas, ovarian cancers, neuroblastoma, bladder cancers and lung cancers. SPF was found of high independent significance in 10 of the 11 studies in which multivariate analyses of prognostic factors had been carried out. Proliferation appears generally to be of higher prognostic significance than ploidy. In view of the wide differences in the biological characteristics of the tumors studied, it is likely that the association between a high proliferation rate and the degree of tumor aggressiveness is a general feature of human solid tumors. However, high proliferative rate of tumor cells is probably not the cause of tumor biological aggressiveness but a variable associated with it. The extent to which cells escape from the regulatory systems which control their proliferation appears to be a good index of tumor progression.

DNA index and cell cycle analysis of primary breast cancer and synchronous axillary lymph node metastases

The DNA Index (DI) and the percentage of cells in S-phase (S-phase fraction, SPF) were measured by flow cytometry in 80 primary breast carcinomas and in 80 accompanying axillary lymph node metastases. The DI in primary tumors and metastases agreed in 61 cases (76%). Cases with diploid primary tumors revealed more constancy of the DI in comparison to the metastases than the cases with aneuploid primary tumors (91% and 70% respectively). The mean values of the SPF were in close agreement in the primary tumors and in the lymph node metastases (6.1% and 6.0% respectively). Differences between the SPF of the two groups could be detected only by the consideration of case-related data pairs. In 50 cases (62%), the percentage of SPF agreed approximately in primary tumors and in the correspondent metastases. The cases with diploid primary tumors revealed more agreement of the SPF in the primary site and the metastases than did cases with aneuploid primary tumors (78% and 56% respectively). In conclusion, diploid carcinomas and their metastases revealed more constancy of the DI and the percentage of SPF than aneuploid carcinomas. These findings agree well with a better prognosis of diploid mammary carcinomas, as reported in the literature. Comparisons between the DI and the SPF in primary tumors and the corresponding metastases could be a source of valuable information on the biological behaviour and the aggressiveness of mammary carcinomas.

Improving the prognostic value of DNA flow cytometry in breast cancer by combining DNA index and S-phase fraction. A proposed classification of DNA histograms in breast cancer

To optimize the prognostic value of DNA flow cytometry in breast cancer the authors calculated several parameters from the DNA histogram, including the DNA index, the size and number of aneuploid peaks as well as S-phase and G2/M-phase cell cycle fractions. Of these, DNA index and S-phase fraction (SPF) proved to be the most valuable prognostic indices. DNA aneuploidy was associated with a three-fold risk of death as compared to DNA diploidy (P less than 0.0001). The highest risk of death was associated with hypertetraploid (greater than 2.20) DNA index, whereas a tetraploid DNA index (1.80-2.20) was associated with a relatively low risk. The SPF had significant additional prognostic value in both DNA diploid (P = 0.0002) and DNA aneuploid (P = 0.02) tumors. By combining DNA index and SPF the authors defined three types of DNA histograms, which were associated with favorable, intermediate, and poor prognosis of the patients. DNA diploidy together with low (less than 7%) SPF (type I DNA histogram) was associated with very favorable prognosis, whereas DNA aneuploidy with high DNA index (greater than 2.20) or high (greater than 12%) SPF (type III DNA histogram) was related to the worst prognosis with approximately eight-fold relative risk of death. In a Cox multivariate regression analysis the type of DNA histogram was an independent and most powerful prognostic indicator in breast cancer. The other independent factors in the Cox analysis were primary tumor size, nodal status, and progesterone receptor status.

Comparison of S-phase fractions measured by flow cytometry and autoradiography in human transplant tumors

The 3H-thymidine labeling index (TLI) and the percentage of cells in the S-phase have been determined by autoradiography and by flow cytometry, (FCM), respectively, in six malignant tumors of human origin transplanted on athymic nude mice. The Dean and Jett model and the graphical model were used to determine the percent of S-phase cells by FCM. Cell cycle analysis was performed using 1) no correction for background; 2) an algebraic function for background correction; and 3) an exponential function for background subtraction. Each of these three data sets was evaluated using both the Dean and Jett model and a graphical model for the evaluation of DNA histograms. The S-phase fractions (SPF) were compared to the corresponding labeling index results. SPF without background correction were 1.54 times higher than the TLI. SPF, after correction using the algebraic model, were 1.29-fold higher than the TLI, whereas SPF obtained after background subtraction according to the exponential model were only 1.05-fold higher than the TLI. Student's t-test revealed significant differences between the mean TLI values (16.25 +/- 9.06) and the mean SPF obtained by FCM without background correction (mean 25.0 +/- 9.36, P less than 0.01), but not between the mean TLI values and the mean SPF percentages after algebraic (mean 21.0 +/- 10.29) and exponential background correction (mean 17.11 +/- 11.59), P greater than 0.05 each. There was no difference between the results obtained using the Dean and Jett model and those obtained using the graphic evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of DNA flow cytometric results and other prognostic factors in primary breast cancer

The percentage of cells in S-phase and DNA-ploidy have been measured in 300 primary mammary carcinomas by means of DNA-flow cytometry (FCM). The data were compared with the age and menopausal status of the patients as well as with the size, regional lymph-node involvement, histologic type, grade and concentration of estrogen (ER) and progesterone (PR) receptors of the tumors. A DNA-diploid distribution of the G0/1-peak was found in 37.6% of the cases. The mean percentage of S-phase fractions was 4.83. DNA-aneuploid tumors had significantly higher amounts of S-phase fractions (6.12%) than DNA-diploid tumors (2.66%). There was also a significant correlation between the DNA measurement data (DNA-ploidy and S-phase fractions) and histologic grade, as well as the content of ER and PR, but not between DNA-ploidy, S-phase fractions, tumor size (T) and evidence of axillary lymph-node metastases. DNA-FCM gives a biological characterization of the tumor in addition to the histopathologic examination. The method can be used as a routine procedure because of the reliability and reproducibility of the results as well as the short time needed for the measurements.