Effect of DNA ploidy classification on prognosis in breast cancer.

A series of 327 breast cancers was analyzed for DNA ploidy by flow cytometry from paraffin-embedded tissue, and the resulting DNA histograms were classified independently by 6 researchers in the field as DNA diploid (Di), aneuploid (An), tetraploid (Te), multiploid (Mu), or technically uninterpretable. The frequency of diploid, aneuploid, tetraploid and multiploid cancers varied from 28 to 41%, 33 to 49%, 8 to 21% and 2 to 6%. According to the scale Di-An-Te-Mu, DNA ploidy was not significantly associated with breast-cancer mortality by 2 classifiers, but if DNA euploid cancers (Di+Te) were tested against non-euploid, or diploid cancers against non-diploid, all classifiers found DNA euploid and diploid cancers to have better prognosis. Mortality associated with diploid or tetraploid cancers decreased with improving histogram quality and increasing uniformity of classification, whereas that associated with aneuploid cancers remained unaltered. Among the cases where all classifiers agreed on ploidy, tetraploid, diploid and aneuploid cancers were associated with 100%, 88% and 68% 5-year survival rates. In this sub-set the S-phase fraction and possibly DNA ploidy were independent prognostic factors, together with histological grade, axillary node status, and primary tumor size.     

DNA aneuploidy and cell proliferation in breast tumors

The cellular DNA content of 30 benign and 180 malignant breast tumors was analyzed by means of flow cytometry (FCM). All benign tumors exhibited a normal DNA content (diploid), whereas 65% of the malignant tumors showed an abnormal DNA content (aneuploid). The ploidy distribution of malignant tumors was bimodal with an increasing frequency near diploid DNA index (DI), and a second group had a DI ranging from triploid to tetraploid. In estimating the degree of malignancy eight independent histomorphologic and cytologic criteria were introduced. A good correlation was observed between DNA content abnormalities and the grade of differentiation of breast carcinomas. The percentage of S-phase cells of DNA aneuploid cell lines was significantly higher than in the diploid ones. The highly differentiated breast carcinomas (Grade 1) indicated lower S-phase values as compared to the undifferentiated (Grade 3) ones. S-phase values estimated by FCM were about two times higher than the 3H-thymidine labeling index (LI) obtained by an in vitro procedure. The data estimated in this study showed that DNA determinations as an adjunct to conventional histopathologic assessment may provide objective clinically relevant information with respect to the degree of malignancy and prognosis of patients with breast carcinoma.     

DNA index of ovarian carcinomas from 56 patients: in vivo in vitro studies

Out of 130 ovarian cancer patients the DNA index of cells from ovarian carcinoma was studied in 56 cases in which cytospin preparations showed the presence of atypical cells. In 24 patients the population had a diploid DNA index (1.0) and in the others the DNA index ranged from 1.2 to 2.0 (tetraploid). No hypodiploid or hypertetraploid populations were detected. Repeated samples from the same patients did not show any significant differences and primary culture did not alter the DNA index. In contrast, cell cycle phase distribution differed greatly from sample to sample, as also the ratio between DNA diploid and DNA aneuploid populations. Primary culture was successful in 57% of the tumours, with a higher percentage of success in DNA aneuploid tumours. After primary culture the ratio between DNA aneuploid cells and DNA diploid cells increased. In relation to the histological gradings of malignancy, DNA aneuploid cells clustered in the highest grade of malignancy. The mean S-phase for tumours with a DNA index of 1.0 was 3.5 and 14.1% for those with DNA index greater than 1. Ovarian carcinomas show a large difference in DNA index between patients even after primary culture.     

DNA content flow cytometry as a prognostic factor for node-positive breast cancer. The role of multiparameter ploidy analysis and specimen sonication

The DNA content was analyzed in paraffin-embedded material from 167 patients with node-positive breast cancer to learn whether specimen sonication and multiparameter ploidy analysis (MPPA) (using DNA content and light scatter) could improve the strength of ploidy as a prognostic variable. Sonicated specimens were found to have fewer aggregates, a lower percentage of cells in S-phase (%S) and G2M phase than the corresponding nonsonicated specimens. The results using MPPA predicted the prognosis better because they allowed detection of small aneuploid peaks in histograms classified as diploid or tetraploid using DNA content alone. Ploidy was a significant univariate factor, and patients with tetraploid tumors had the best survival. In the multivariate analysis, if other routine factors were examined preferentially, ploidy and %S did not provide additional prognostic information for survival. This study of paraffin-embedded breast cancers suggested that sonication and MPPA may improve the ploidy analysis in certain cases and that tetraploidy may be a favorable ploidy pattern in this group.     

Common acute lymphoblastic leukemia characterized by four different DNA stemlines with heterogeneity in RNA content, antigen expression and sensitivity to chemotherapy

Four subpopulations of cells with different DNA content were present in the bone marrow of a pediatric patient with acute lymphoblastic leukemia. Flow cytometry of DNA/RNA and DNA/surface antigen expression enabled the identification and characterization of diploid, hypertriploid, tetraploid and hypertetraploid leukemic cells. This was not appreciated by cytogenetic analysis, which identified only some tetraploid cells (3/20 metaphases). Common acute lymphoblastic leukemia antigen was expressed in all aneuploid and also on 17% of diploid cells. Quantitative CALLA expression was unrelated to ploidy and cell size. Cellular RNA content paralleled ploidy, i.e. the more aneuploid cells had increased RNA content and there was pronounced RNA heterogeneity within each DNA stemline. The different subclones showed almost identical stages of early B-cell differentiation. The early pre B-cell antigens BL1 and BL2 were expressed in approx. 80 and 60%, respectively, of aneuploid leukemic cells. Cytoplasmic immunoglobulin heavy chain was also present. Clonal excess of lambda light chain immunoglobulin on the cell surface was present on less than 10% of hypertriploid, tetraploid and hypertetraploid leukemic cells indicating differentiation of a subpopulation of aneuploid leukemic cells to mature B cells. This was not seen for any diploid cells. The heterogeneity of the different subpopulations was also evident in the differences in response to chemotherapy: the hypertriploid and hypertetraploid subpopulations were most sensitive to initial induction chemotherapy.     

DNA ploidy and S-phase in primary malignant melanoma as prognostic factors for stage III disease.

In 82 patients with stage III malignant melanoma, the primary tumours were investigated by DNA flow cytometry. The tumours were classified as DNA diploid (n = 36), tetraploid (n = 11) and aneuploid (n = 35). By univariate analysis a significant correlation with post-recurrence survival was found for time to first metastasis, DNA-ploidy and S-phase fraction. By multivariate analysis, significant prognostic variables were found to be the time to first metastasis (P = 0.006), and ploidy (P = 0.011). Patients with diploid melanomas and a long recurrence-free interval had a median post-recurrence survival time of 45 months compared to 18 months in patients with DNA aneuploid tumours and an early recurrence. The S-phase could be estimated in 47 primary melanomas and was found to be a significant prognostic variable (P = 0.017). The median survival was 45 months for patients with melanomas with a S-phase fraction below 5%, and 19 months for melanomas with S-phase above 10%. The prognostic value of the S-phase remained significant even after adjustment for recurrence-free interval and DNA ploidy.     

Flow cytometric analysis of DNA and cell proliferation in ovarian tumors

DNA content in tumor cells from 50 patients with ovarian tumors was analysed by flow cytometry (FCM). Solid tissue samples were processed to obtain monodispersed cells. Staining for DNA analysis was achieved with ethidium bromide and mithramycin. Peripheral blood lymphocytes were used as reference diploid cell population. All benign ovarian tumors exhibited only diploid cells. DNA aneuploid cell lines were found 66.6% of serous carcinomas and in 80% of malignant granulosa cell tumors. The S-phase fraction of DNA diploid cells in benign ovarian tumors (S = 2.4 +/- 1.2%) was smaller than those of malignant tumors (S = 8.2 +/- 5.2%). DNA aneuploid cell populations in serous carcinomas display a higher S-phase fraction (S = 19.2 +/- 9.3%) than DNA diploid cells (S = 11.7 +/- 3.2%). No major differences were obtained between primary ovarian tumors and their metastases, as far as degree of aneuploidy and S-phase fraction are concerned. A high degree of correlation was established between the grade of differentiation of ovarian tumors and the DNA ploidy abnormalities.     

In treating localized prostate cancer the efficacy of cryoablation is independent of DNA ploidy type

While the prognostic value of DNA ploidy has been well established for radical prostatectomy, external beam radiation, brachytherapy and androgen deprivation therapy its role as a survival outcome predictor for prostate cancer patients treated with cryoablation has not yet been examined. Anecdotal evidence suggesting that cryoablation may be independent of DNA ploidy type led to the implementation of the current study. Retrospective analysis of data including flow digital cytometry was performed on 447 archival specimens taken from patients who had undergone cryosurgical ablation of primary prostate cancer. Five-year biochemical disease free survivals (bDFS) (defined as PSA thresholds of 0.5 and 1.0 ng/ml) were determined with Kaplan-Meier analysis. Patients were grouped according to DNA ploidy types then stratified by Gleason grade, risk group, pre-surgical PSA level, and disease stage. Mean and median age of the cohort was 65 and 64.6 years. Mean follow-up was 65.7 months. The DNA ploidy status of the population was found to be 59% diploid, 13% tetraploid, and 28% aneuploid. Using PSA < 1.0 ng/ml criterion, the bDFS rates for diploid, tetraploid, and aneuploid were 78%, 75%, and 79% respectively. The bDFS rates using a PSA < 0.5 ng/ml criterion were 67%, 59%, and 69% for diploid, tetraploid, and aneuploid groups. No significant outcome differences were found in stratified analysis. This investigation demonstrates that the efficacy of cryoablation is independent of DNA ploidy type.     

DNA flow cytometry and prognostic factors in 1331 frozen breast cancer specimens

Breast cancer proliferative capacity as determined by the DNA thymidine labeling index, along with estrogen and progesterone receptor status, is highly predictive for risk of relapse and overall survival. Recently, DNA ploidy and proliferative capacity (S-phase fraction [SPF]) as determined by flow cytometry have also shown significant prognostic value. The authors have developed a technique which allows a 50 to 100 mg aliquot of the same frozen breast tumor specimen routinely employed in steroid receptor assays, to be assayed for both DNA ploidy and SPF by flow cytometry. Of the 1331 tumors examined, DNA histograms were evaluable for ploidy in 89% (1184) of specimens examined; 57% of these were aneuploid. Adapting a trapezoidal model to estimate SPF in both diploid and aneuploid tumors, the authors found 81% (1084) to be evaluable for SPF, with a median SPF of 5.8% for the entire population. The median SPF was significantly lower in diploid tumors (2.6%) than in aneuploid tumors (10.3%, P less than 0.0001). Both aneuploidy and high SPF were strongly associated with absence of steroid receptors. Aneuploid tumors showed more striking differences in the frequency of high S-phase values with respect to receptor status and age or menopausal status, whereas diploid but not aneuploid tumors showed lower SPF in node-negative versus node-positive patients. Because it is particularly important to identify the high-risk minority of node-negative patients, the authors examined the node-negative group separately. High SPF subgroups appeared in each category of receptor status and age or menopausal status within the node-negative group, suggesting that SPF will be an independent prognostic factor. With the DNA flow cytometric methods used here, it is now practical to determine ploidy and SPF for nearly every breast cancer patient. These factors, which show associations with established prognostic factors, such as receptor status can now be fully evaluated for their prognostic significance in broad patient populations.     

Genetic alterations in DNA diploid, aneuploid and multiploid colorectal carcinomas identified by the crypt isolation technique

Loss of heterozygosity (LOH) and microsatellite instability (MSI) commonly occur in colorectal carcinomas. However, the role of these genetic alterations in determining DNA ploidy status of tumors (diploid, aneuploid and multiploid) remains unclear. In the present study, we attempted to clarify the relationship between genetic alterations and DNA ploidy status. Crypt isolation coupled with DNA cytometric sorting and polymerase chain reaction assay (17 microsatellite markers) were used to study allelic losses and MSI in 59 colorectal carcinomas (diploid, 15; aneuploid, 10 and multiploid, 34). Of the 15 diploid carcinomas, 6 exhibited MSI in which allelic losses were rarely found. The other 9 diploid tumors mostly exhibited allelic losses, but none displayed MSI status. Whereas allelic losses frequently occurred in the aneuploid carcinomas and the aneuploid populations of multiploid carcinomas, they were rarely detected in the diploid populations of multiploid carcinomas. MSI status was not observed in aneuploid carcinomas nor in either population of multiploid carcinomas. Although multiploid carcinomas genetically resemble aneuploid carcinomas in the expression of the severe LOH phenotype, the genetic alterations seen in the diploid populations of multiploid carcinomas may differ from those of diploid carcinomas. Furthermore, all diploid, aneuploid and both the diploid and aneuploid fractions of the multiploid tumors that were non-MSI exhibited a high rate of LOH, suggesting that LOH is independent of the tumor's ploidy status.     

Prognostic significance of DNA ploidy in patients with stage II colorectal cancer

DNA ploidy status associated with colorectal cancer has been investigated widely in recent years. But the relationship between DNA analysis and prognosis has not been confirmed.[1(3] Some investigations showed that DNA aneuploid status was associated with lymph node involvement and poor differentiation, and thus may predict a poor clinical outcome in patients with colorectal cancer. These observations suggest that DNA ploidy abnormality may influence the development and progression of colo…     

Pretherapeutic flow cytometric DNA investigations in radiotherapy patients with maxillo-facial carcinomas

In order to analyze the possible meaning of cellular DNA content and cell cycle phases for the radiosensitivity and the prognosis of human malignant tumors, flow cytometric measurements have been performed in biopsies of 131 patients with histologically proven squamous cell carcinomas of the maxillo-facial region. In two-thirds of the patients (88/131; 67%), aneuploid tumor cell lines have been found, only 33% (43/131) had a diploid DNA distribution pattern. The average DNA index (DI) of the aneuploid carcinomas was 3.4 +/- 0.6 (normal nonmalignant tissue DI = 2.0). The frequency of S-phase cells, which represents the "proliferative activity", was between 4.8 and 63.2%, regardless of the ploidy stages. The aneuploid carcinomas had about twice as many S-phase cells (mean 23.7 +/- 11.8%) than diploid tumors (mean 12.7 +/- 4.8%). Mean survival for patients with diploid carcinoma and aneuploid carcinoma was 12 and 9.5 months, respectively. Concerning the relationship of S-phase frequency and survival times in our material there was a high negative statistical correlation (Spearman-Rank test) in patients with diploid carcinomas. A high S-phase fraction resulted in short survival times. No correlation was found in the aneuploid carcinomas: patients with tumors in high S-phase values in their biopsies showed no difference in prognosis in comparison to tumors with lower S-phase fractions.     

DNA aneuploidy and low S-phase fraction as favourable prognostic signs in metastatic melanoma

The prognostic value of cellular DNA content in melanoma metastases was investigated by flow cytometric analysis of fresh or paraffin-embedded tumour blocks from 95 consecutive patients referred to the Helsinki University Central Hospital Melanoma Team. Thirty-three per cent of the tumours were DNA diploid and 67% DNA aneuploid. S-phase fractions were lower in DNA diploid than in DNA aneuploid tumours (10.7% and 17.6%). Tumour ploidy and S-phase fraction were shown by multivariate Cox model analysis to be independent prognostic variables and major determinants of survival after first recurrence. Surprisingly, patients with DNA aneuploid tumours and with tumours with low SPF survived significantly longer than those with DNA diploid or high SPF tumours. This exceptional finding of favourable prognosis for DNA aneuploid tumours was more prominent among patients receiving intensive systemic therapy and among patients with stage IV disease, probably indicating a tendency for DNA aneuploid tumours to have higher sensitivity to systemic therapy.     

Survival of large bowel carcinoma patients with different DNA ploidy

One hundred patients operated for large bowel carcinoma were divided into a distinct aneuploid group of 63, and a near diploid one of 37. Flow cytometry was used for determination of the DNA ploidy pattern. All tumours in the aneuploid group contained one or more aneuploid cell populations. All patients were followed clinically from 3.5 to 7.8 years. The corrected 5 year survival was 64% and 49% for patients with near diploid and aneuploid tumours, respectively (not significant). Significant differences in corrected survival time were not observed for Dukes' stages A, B, and C patients pooled, nor for Dukes' stage D patients. However, for Dukes' stage C patients alone, there was a tendency (P = 0.10) for patients with near diploid tumours to show a better survival. A highly significant predominance of aneuploid tumours was seen in males, in contrast to an equal distribution of aneuploid and near diploid tumours in females. A slight predominance of aneuploid tumours in the left colon and rectum was seen. Both these findings indicate the influence of environmental factors (hormonal, anatomical, phenotypical) on the development of tumours with a particular DNA ploidy pattern.     

Selection of tumour cell subpopulations occurs during cultivation of human tumours in soft agar. A DNA flow cytometric study

To examine whether selection of tumour cell subpopulations occurs during cultivation in soft agar, we compared in 23 human tumours of different histological types the DNA content of cells from colonies formed in soft agar (method of Courtenay and Mills, 1978) with that of the original tumour cells. The ploidy as well as the fraction of cells in S phase were determined from DNA histograms after staining of the nuclei with a propidium-iodide procedure and flow cytometric recordings. In 8 of 17 aneuploid tumours analysed, specific aneuploid subpopulations disappeared during cultivation or new aneuploid populations, not demonstrable in the original cell suspensions, appeared in the colonies. In 9 cases identical aneuploid populations were found in the colonies and the tumours. In one of 6 diploid tumours examined, aneuploid cell populations not revealed in the original cell suspension, were found in addition to diploid cells, whereas 5 tumours gave rise to colonies containing a purely diploid population. The results show that in a variety of human malignant tumours cultivation in soft agar may select specific aneuploid tumour cell populations.     

Clinical DNA flow cytometry

Modal DNA values of tumours from various sites may exhibit (1) a diploid-near diploid distribution, (2) an exponential distribution in the tetraploid to triploid range, or (3) a log-normal distribution in the triploid to tetraploid range. Examples of these various types of distribution are non-Hodgkin's lymphoma (1), aneuploid prostate carcinoma (2), aneuploid colon, breast, cervix and testicular carcinomas (3). These differences indicate dissimilarities in tumour development. In aneuploid tumours from the same site both tetraploid exponential and triploid-tetraploid log-normal distributions may occur. In bladder carcinoma these are related to grade. Modal DNA values in tumours are 10% higher than would be expected from modal chromosome numbers. This difference seems not to be due to a relative increase in large-sized chromosomes or due to technical shortcomings. Chromosome studies also show the possibility of the existence of near diploid malignant cells in grossly aneuploid tumours. Modal DNA values are connected with functional tumour properties by the proportion of S-phase cells. The significance of the latter is exemplified by follow-up of patients with bladder and cervix carcinoma.     

Flow cytometric DNA index and S-phase fraction in breast cancer in relation to other prognostic variables and to clinical outcome.

One frequently used classification of flow cytometric DNA ploidy status (diploid versus nondiploid) was compared with a division into seven ploidy classes based on DNA index (DI) and number of cell populations (hypodiploid, diploid, near-hyperdiploid, hyperdiploid, tetraploid, hypertetraploid, and multiploid). The latter ploidy classification showed a better correlation with prognosis and other prognostic factors (i.e., lymph node involvement, estrogen and progesterone receptor status, and S-phase fraction). The improvement in correlation was mainly due to the identification of near-hyperdiploid cases (DI 1.00-1.14) which could be combined with the diploid cases to form a group with favourable prognosis. In contrast to cases with a small increase in DNA content (near-hyperdiploid), those with a small decrease of DNA content (hypodiploid) manifested a more aggressive disease. In multivariate analysis, S-phase fraction (SPF) was a more important prognostic factor than both the improved or the conventional ploidy classification.     

Laser scanning cytometry for the detection of neoplasia in urologic cytology specimens

BACKGROUND: The objective of the current pilot project was to assess the efficacy of laser scanning cytometry (LSC) for DNA ploidy analysis of atypical urologic cytology specimens to enhance the distinction between benign and malignant changes. METHODS: Forty selected urologic cytology specimens that previously had been categorized as normal, atypical, or malignant were studied. Nuclear propidium iodide and fluorescence intensity measurements were converted to pixel values, which were used to create scattergrams that excluded debris and cell clusters from ploidy analysis, creating a gated (isolated) region of predominantly single cells for LSC ploidy analysis. Integral histograms then were created to show the number of cells present in diploid, tetraploid, and aneuploid peaks; these histograms also were used to assess DNA ploidy. RESULTS: Ten normal specimens, 10 malignant specimens, and 20 atypical specimens were examined to assess the efficacy of LSC ploidy analysis. Normal and malignant specimens generated reference histograms for comparison with the atypical specimens and exhibited 90% specificity and 100% sensitivity. Ten atypical aneuploid specimens had histogram and scattergram patterns similar to those produced by malignant specimens and, using the cytometer's relocation feature, the presence of atypical cells was confirmed in the aneuploid regions. CONCLUSIONS: The authors determined that DNA ploidy analysis of atypical urologic cytology specimens using LSC is a useful adjunct tool for identifying malignant specimens that lack sufficient cytologic criteria for diagnosis by light microscopy alone. However, LSC is time consuming and requires expensive equipment.     

Prognostic value of S-phase fraction and DNA ploidy studied with in vivo administration of bromodeoxyuridine on human gastric cancers

The authors studied the prognostic values of DNA ploidy pattern and proliferative activity with in vivo administration of bromodeoxyuridine in human gastric cancers. Fresh specimens surgically removed from 117 patients with gastric cancer were investigated by flow cytometric study using a monoclonal antibody to bromodeoxyuridine. DNA ploidy patterns were classified into four types according to the bivariate BrdUrd/DNA distribution: D1, tumors with single diploid population; D2, tumors which showed mosaic of diploid and aneuploid population; A1, tumors with single aneuploid population; and A2, several aneuploid populations without diploid population. The numbers of cases of each ploidy pattern were as follows: D1, 36 cases (30.8%); D2, 38 cases (32.5%); A1, 15 cases (12.8%); and A2, 27 cases (23.1%). DNA ploidy pattern and S-phase fraction (SPF) showed no relation with clinicopathologic findings, except for type A2. In type A2, lymph node metastasis and lymphatic vessel invasion were observed more often than type D1. The SPF calculated from the bivariate BrdUrd/DNA distribution was higher in aneuploidy (D2, A1, and A2) than in diploidy (D1) (P less than 0.01). Also, A2 exhibited a higher SPF than A1 (P less than 0.01). Furthermore, SPF correlated with DNA index significantly (P less than 0.01). Patients who showed aneuploid tumors, DNA ploidy type A2, or SPF of more than 10% survived 3 years less than those with diploid tumors, DNA ploidy type D1, or SPF of less than 10%, respectively (P less than 0.05). By analyzing with the Cox's proportional hazard's model, it is revealed that DNA ploidy and SPF are one of the independent factors of prognostic significance. The results indicated that the patients with aneuploid tumors or highly proliferative tumors had a poor prognosis and that DNA ploidy pattern and SPF were useful prognostic factors for gastric cancers.     

Ploidy assessment of benign and malignant ovarian tumors by flow cytometry. A clinicopathologic study

In a prospective study, 112 fresh ovarian tumor samples were collected from 83 consecutive patients. Cellular DNA content was measured by flow cytometry. All the benign (n = 24) and semimalignant (n = 6) tumors were diploid. Of 50 malignant tumors, 24 (48%) were diploid and 26 (52%) were aneuploid. Aneuploidy was more frequent in the advanced stages of the disease, in tumors of low degree of differentiation, and in older patients. The patients with aneuploid tumors had smaller primary tumors and more often ascites. The fraction of cells with S-phase DNA content was higher in the aneuploid tumors. No association was seen to the tumor type. Ploidy determination is objective and reproducible. Aneuploidy associates to most negative prognostic factors in ovarian carcinoma and may reflect the aggressiveness of the tumor. The ploidy status may be taken into consideration in the stratification of patients of comparable risk for treatment studies.