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.     

Benign metastasizing giant cell tumors of bone. A DNA flow cytometric study

Approximately 2% of histologically benign giant cell tumors (BGCT) of bone are complicated by lung metastases, which can progress despite their benign histologic appearance. Almost all BGCT studied by DNA flow cytometry (FCM) have been reported to be diploid. However, the very few cases with lung metastases previously analyzed were all aneuploid. To assess the usefulness of DNA FCM in predicting the metastatic potential of BGCT, seven metastasizing BGCT were studied by DNA FCM using paraffin-embedded tissue. Five were purely diploid, one was tetraploid, and one was aneuploid. The primary and the metastasis showed the same DNA distribution in all but the tetraploid case, in which the metastasis was purely diploid. A single patient, who was in the diploid group, had unresectable tumor in the lungs; she remains alive with stable disease at 30 months. The other six patients, who underwent complete resections of their lung metastases, are free of disease. These results suggest that DNA FCM is not a sensitive method for predicting the metastatic potential of BGCT since most metastasizing cases appear to be diploid.     

Oncocytic tumours of the salivary gland, kidney, and thyroid: nuclear DNA patterns studied by flow cytometry

Nuclear DNA ploidy studies were performed by flow cytometry on extracted nuclei from 12 oncocytic tumours of the salivary gland, 65 oncocytic tumours of the kidney, and 37 oncocytic tumours of the thyroid gland from the pathology archives of the Mayo Clinic. In order to provide an interesting clinical spectrum, three different classes of well-differentiated oncocytic tumours were selected for examination. Salivary gland oncocytic tumours were chosen for their generally benign behaviour. Oncocytic thyroid cancers exhibiting malignant potential because of local invasion, were thought to represent the opposite extreme of aggressiveness. Renal oncocytic tumours were known to demonstrate an intermediate degree of malignancy. All of the oncocytic salivary gland tumours showed a 'normal' DNA histogram and had a benign clinical course. For the oncocytic tumours of the kidney, 45% of DNA histograms were normal, 40% exhibited a significant increase in the DNA tetraploid/polyploid (4C) peak, and 15% showed a DNA aneuploid peak. Three patients with a DNA tetraploid pattern developed tumour metastasis and two have died from metastatic renal cancer. Among the oncocytic thyroid cancers, 27% were normal, 22% exhibited an increased DNA tetraploid peak, and 51% had a distinct DNA aneuploid peak. None of the thyroid tumour patients with a normal DNA pattern or with an increased DNA tetraploid peak died as a result of thyroid malignancy. In contrast, 58% of patients whose thyroid tumours showed a DNA aneuploid peak subsequently died from thyroid cancer.     

Large-scale genomic instability predicts long-term outcome for women with invasive stage I ovarian cancer.

BACKGROUND: The objective was to evaluate the value of DNA ploidy using high-resolution image cytometry in predicting long-term survival of patients with early ovarian cancer. PATIENTS AND METHODS: A retrospective analysis of 284 cases with FIGO stage I ovarian carcinoma treated during the period 1982-1989 was performed. Clinical follow-up information was available for all patients. RESULTS: Patients with diploid and tetraploid tumors had a 10-year relapse-free survival of 95% and 89%, respectively, compared with 70% and 29% for polyploid and aneuploid tumors, respectively. DNA ploidy analysis was the strongest predictor of survival in multivariate analysis (diploid/tetraploid versus polyploid/aneuploid; relative hazard 9.0) followed by histological grade, including clear cell tumors in the group of poorly differentiated tumors (grade 1-2 versus grade 3 or clear cell; relative hazard 2.7), and FIGO stage (Ib/Ic versus Ia; relative hazard 2.0). In a stratified Kaplan-Meier analysis, patients with grade 1-2, diploid or tetraploid tumors had a 10-year relapse-free survival of 95%, forming a low-risk group. Patients with grade 3 or clear cell, diploid or tetraploid tumors had 10-year relapse-free survival of 86%, forming an intermediate-risk group, while all patients with aneuploid/polyploid tumors formed a high-risk group, with 10-year relapse-free survival of 34%. CONCLUSIONS: This study points to the importance of including DNA ploidy analysis by image cytometry when selecting patients with early ovarian cancer for adjuvant treatment after surgery.     

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.     

Carcinoma of the anal canal and flow cytometric DNA analysis

Using flow cytometric DNA analysis of paraffin embedded tissue, DNA histograms were successfully obtained from the anal cancers of 117 patients. DNA diploid patterns were given by 82 cancers (70%) and DNA non-diploid patterns by 35 cancers (30%): 15 DNA aneuploid, 20 DNA tetraploid. Well differentiated squamous cell cancers were mainly DNA diploid, while a larger proportion of poorly differentiated and small cell cancers were DNA non-diploid. The large majority of stage A cancers were DNA diploid. A greater proportion of tumours that had invaded through the anal sphincter or had lymph node metastases or distant spread were DNA non-diploid. Prognosis was slightly poorer for patients with DNA non-diploid cancers when compared to patients with DNA diploid tumours (P = 0.08) and significantly poorer for individuals with DNA aneuploid anal cancers (P = 0.037). However, in a multivariate analysis model, the DNA ploidy pattern of an anal cancer was not of independent prognostic significance alongside tumour histology and tumour stage.     

Flow cytometric analysis of DNA content in human bladder tumors and irrigation fluids

Flow cytometry (FCM) was used to study the DNA distribution of 99 tumor biopsy specimens and 41 bladder irrigation samples from patients with transitional cell carcinoma of the bladder. For tumor biopsy and cystectomy specimens, the frequency of aneuploidy increased with advancing tumor stage and grade. All T0 tumors were diploid. Twenty-seven percent of T1, 71.4% of T2, and 75% of T3 and T4 tumors were aneuploid. All Grade I tumors were diploid. Thirty percent of Grade II and 76.9% of Grade III tumors were aneuploid. The frequency of aneuploidy of tumors in the early stages (Ta, T1) is similar to the incidence of subsequent progression by these tumors described in the literature. For irrigation fluids, the relationship between grade and stage and the frequency of aneuploidy was similar to the relationship seen with tumor specimens. All four patients with only carcinoma in situ had aneuploid cells in their irrigations. The comparison of FCM data of bladder biopsy and bladder irrigation from the same cystoscopic evaluation suggests adequate representation of tumor cells in the irrigation fluids for almost all cases. The authors conclude that DNA ploidy analysis by FCM appears useful in a clinically important group of patients with aneuploid superficial tumors of moderate or high grade. Bladder irrigation analysis appears useful in the follow-up of patients with a history of carcinoma in situ and those with aneuploid tumors.     

Cytophotometric studies of the nuclear DNA content in cartilaginous tumors.

The histopathological differentiation between chondromas and low-grade malignant chondrosarcomas can be difficult. For this reason we studied in 37 different cartilaginous tumors the mitotic index and the Feulgen DNA content using a scanning-integration cytophotometric technique. In 23 chondromas the Feulgen DNA content was diploid and showed a unimodal normal distribution. The number of mitoses was 0--0, 5%. The nuclei of a chondroblastoma were also diploid and the Feulgen DNA content was normally distributed. The mitotic index was 1% and few tetraploid nuclei, which were probably G2 nuclei, were observed. In two chondromyxoid fibromas, the average Feulgen DNA content was diploid and normally distributed. Several tetraploid nuclei were noted. The mitotic index was respectively 0.25% and 1.75%. Recurrence was noted in the first case. The Feulgen DNA content and mitotic index were clearly different in the chondrosarcomas. The distribution of the DNA content was bimodal or unimodal in low-grade chondrosarcomas. The mitotic index was less than 3%. In high-grade malignant chondrosarcomas, the histograms were broad unimodal or aneuploid. The mitotic index was above 5%.     

DNA content of human kidney carcinoma cells in relation to histological grading.

Ploidy and cell-cycle stage were determined by flow cytometry (FCM) in 46 human renal carcinomas. Cell populations with aneuploid DNA were detected in 46% of these. In the investigated samples, the fraction of cells with abnormal DNA content varied from 8 to 100%. The proliferative activity was generally low as indicated by the small fractions of cells in S and (G2 + M) phases. This was confirmed by the labelling indices on autoradiographic slides. The fraction of cells in phases S and (G2 + M) for tumours that were pre-irradiated with 15 or 25 Gy before nephrectomy was only slightly less than in unirradiated tumours. Comparison of the FCM ploidy with the results of histological grading showed that all cases classified as the most malignant grades IV or IIIB (according to the nuclear and to the combined grading system of Syrjänen and Hjelt (1978) were hyperdiploid. On the other hand, 45% of the hyperdiploid and 89% of the diploid tumours were of the low grades I and II. After a follow-up for 6 months to 2 years, 8/17 patients with hyperdiploid and only 1/14 patients with diploid tumours have died or relapsed with multiple metastases. The results indicate that the aneuploidy of tumours, measured by FCM, might provide useful additional information for prognosis.     

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.     

DNA analysis by flow cytometry, response to endocrine treatment and prognosis in advanced carcinoma of the breast

The relationship between DNA content of mammary cancer and subsequent response to endocrine therapy was studied in 136 patients with advanced disease. All were treated with tamoxifen or ovarian ablation as first-line systemic therapy after relapse and were evaluable for response according to UICC criteria. DNA characterisation by flow cytometry was used on formalin fixed paraffin-embedded samples of tumour. Tumours were grouped according to DNA index into diploid (n = 52, 38%), 'tetraploid' (n = 46, 34%) and 'other DNA-aneuploid' (n = 38, 28%). The highest proportion of oestrogen receptor positive tumours (ER + ve) was found in the 'tetraploid' tumours (38/46, 85%, Chi-square = 8.53, P less than 0.02), and response rates, (SD + PR + CR), were 26/52 (50%), 34/46 (74%), and 15/38 (39%) respectively (Chi-square = 10.88, P less than 0.005). Patients with diploid or 'tetraploid' tumours survived longer and stayed in remission longer than those with 'other DNA-aneuploid' tumours. We suggest that 'tetraploid' or 'near tetraploid' human mammary tumours may comprise a distinct group of endocrine responsive tumours within the overall group of aneuploid tumours. The conventional interpretation of DNA histograms, grouping into diploid and aneuploid, may be masking important features of some tumour groups.     

Response to chemotherapy (irinotecan plus 5-fluorouracil) in colorectal carcinoma can be predicted by tumour DNA content

OBJECTIVE: The aim of this study was to identify markers that might predict response to chemotherapy. Postoperative chemotherapy improves the outcome in stage III colon cancer and is widely accepted as a standard therapy, but there are currently no reliable predictors to identify and select patients that will benefit. METHODS: Using DNA image cytometry, the DNA content was determined from the isolated nuclei of 56 primary colorectal carcinomas of patients who received chemotherapy (either irinotecan or irinotecan plus 5-fluorouracil and folinic acid) for advanced disease. Response to chemotherapy could be reliably evaluated in 53 patients. RESULTS: The modal DNA content (ploidy status) of the tumour correlated with the observed response to chemotherapy (p = 0.01). An objective response was observed in 56% of patients whose tumour histograms displayed tetraploid, peri-tetraploid or multiploid patterns of peaks, compared with 19% in patients with diploid, peri-diploid or aneuploid peaks. Notably, 86% (6/7) of patients whose tumours displayed a multiploid peak pattern showed an objective response and 1 patient had stable disease. CONCLUSIONS: This study suggests that modal DNA content can be used to predict a patient's response to chemotherapy in advanced colorectal carcinoma. This may help in identifying patients who will benefit most from therapy for advanced colorectal cancer.     

Dna Flow Cytometry in Carcinoma of the Prostate for Diagnosis, Prognosis and Study of Tumor Biology

Flow cytometry has been used to measure the cellular DNA content in fine-needle aspirates of a large number of patients with untreated prostate carcinomas. the tumors were subdivided into diploid, tetraploid aneuploid and non-tetraploid aneuploid with one or several aneuploid cell populations. the clinical relevance of this subdivision is supported by studies of the metastatic potential of the tumors and the outcome of the disease by follow-up of the patients. Changes were found in the proportion of the various ploidy classes with tumor stage. These were typical for the behavior of a 3-compartment system. Thus, the proportion of diploid tumors decreased exponentially with stage, that of the tetraploid-aneuploid tumors increased to maximum at intermediate stages, while the non-tetraploid aneuploid tumors increased exponentially after some delay. This strongly supports the concept of a con-tinous development of the prostate carcinoma from low grade to high grade connected with the doubling of the near-diploid genome of the tumor, and followed by successive loss of chromosomes from the near-tetraploid tumor. Further support of this concept is gained by the study of repeated fine-needle aspirates and the observation of coexisting diploid and aneuploid cell populations in the developing tumor. Clinical consequences of this concept are discussed.     

A flow cytometric analysis of 23 carcinoid tumors

Twenty-three carcinoid tumors were investigated from paraffin-embedded tissue with flow cytometry (FCM) in order to correlate the DNA ploidy with clinical variables. DNA aneuploidy was found in ten tumors (45%) and one tumor was classified as tetraploid. Diurnal urinary excretion of 5-hydroxy indolic acetic acid (5-HIAA) was known to be elevated in seven of eight diploid tumors and in four of seven aneuploid carcinoids with distant metastases. Six (55%) of the diploid tumors had not given rise to metastases at the time of diagnosis, compared with three (30%) of the aneuploid tumors. Six of seven patients with an aneuploid tumor and three of five patients with a diploid tumor, observed for at least 10 years, died of the disease. It was concluded that, unlike in earlier studies with static DNA cytometry, DNA aneuploidy is common in human carcinoid tumors and may occur in tumors secreting biogenic amines.     

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.     

DNA content in high and intermediate grade non-Hodgkin's lymphoma-prognostic significance and clinicopathological correlations

Flow cytometric (FCM) estimation of DNA content has been performed on tumour tissue from 197 patients with high and intermediate grade non-Hodgkin's lymphoma (NHL) to investigate the clinicopathological correlations and prognostic significance of DNA ploidy and proliferative activity. Fifty-one per cent of tumours were diploid; the remaining non-diploid tumours were near diploid (14%), aneuploid (28%) and tetraploid (7%). In 81 tumours multiple analyses were performed from different regions of the tumour, ploidy discrepancy was seen within the same tumour in 13/81 tumours (16%), and intra-tumour variation in proliferative index (PI) in 72 tumours was estimated at +/- 5%. Ploidy status did not correlate with histological subtype (Kiel or Rappaport), Ann Arbor stage or the site of disease at presentation. There was no significant difference in response rate, relapse-free survival (RFS) or overall survival rate between the different ploidy categories. Tumour proliferative index (PI) varied markedly between patients (range 2-51%, median 14%). A significant association was observed between PI and histological subtype in the Kiel classification (P = 0.001). The median PI for the lymphoblastic lymphomas was 20% compared with 10% for the centrocytic tumours. An elevated PI was significantly associated with a reduced rate (P = 0.023), with 71% of patients with a low PI (less than 20%) achieving complete remission (CR) compared with 49% patients with a high PI (greater than 20%). Despite this correlation with CR, PI was not significantly associated with overall survival. When the DNA data was combined with over 20 other potential prognostic factors in multivariate analysis, ploidy and proliferative activity did not prove to be of independent prognostic significance for response, RFS or overall survival. In 20 patients additional biopsy material was available from the site of subsequent relapse. In these cases, although the histology at relapse remained unchanged, ploidy status altered in 13/20 patients, and there was a significant rise in tumour PI at relapse compared with the initial pre treatment biopsy (P = 0.017). We conclude that in high and intermediate grade NHL, DNA ploidy as assessed using conventional FCM analysis is not significantly associated with clinical outcome. However, proliferative activity does correlate with histological subtype and response to therapy, and this parameter warrants further evaluation in future studies.     

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.     

Measurement of S-phase fraction and ploidy in sequential fine-needle aspirates from primary human breast tumours treated with tamoxifen.

Sequential fine-needle aspirates (FNAs) for cytodiagnosis and flow cytometry were taken from 21 patients with primary breast carcinoma at intervals ranging from 1 to 3 months after the commencement of first-line tamoxifen therapy. Nine patients achieved a sustained complete or near complete response over a 3-9 month period. The tumour cells from seven out of nine of these patients were initially aneuploid, while the remaining two patients had diploid tumours. An analysis of sequential FNAs showed that, in three out of the seven aneuploid tumours, only benign epithelial cells could be detected by cytology in the post-tamoxifen sample. In the remaining six cases, including the two diploid tumours, there was no change in ploidy but a reduction in S-phase fraction (SPF) to approximately 50% of the pretreatment level. In all cases, these changes in ploidy or SPF were seen with a mean lead time of 4 months before the tumour had reached clinical complete remission. None of these patients have relapsed after a mean follow-up period of 18 months. The tumours of 12 patients achieved no more than a temporary partial response to primary tamoxifen therapy. In seven out of eight of these cases, which were all initially aneuploid, sequential FNAs during tamoxifen therapy revealed either an increase or no change in the SPF with the tumour remaining aneuploid. In the remaining four cases the tumours were all recorded as being diploid in the pretreatment sample. However, although three of these cases had a temporary partial response to tamoxifen, an aneuploid component was picked up in repeat sequential FNAs with a mean lead time of 5 months before clinical confirmation of eventual disease progression. We conclude that changes in ploidy and SPF detected by flow cytometry may predict initial response and the likelihood of relapse of breast tumours to tamoxifen before clinical changes become evident. These data justify a larger study.     

Tumour growth rate and DNA flow cytometry parameters as prognostic factors in metastatic melanoma.

The prognostic value of flow cytometric parameters and tumour growth rate of melanoma metastases under the mouse renal capsule was investigated for tumours from 117 consecutive patients referred to the Helsinki University Central Hospital Melanoma Team. DNA flow cytometry (FCM) was interpretable for the tumours of 114 patients, and growth rate analysis for 82 patients, both results being available from 79 patients. Thirty-six percent of the tumours were DNA diploid and 64% DNA aneuploid. 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. Patients with DNA diploid or aneuploid tumours survived a median 16 and 27 months, respectively. A high growth rate of tumour sample in vivo under the mouse renal capsule tended to be a sign of poor prognosis, although not reaching statistical significance. Combining the results of FCM, tumour growth rate and TNM stage, we propose a highly efficient prognostic scoring method. Patients with a score above 0.75 had a median survival of 11 months compared to 30 months among patients scoring under 0.75 (P less than 0.0001). This score was the most significant (P less than 0.0001) prognostic factor in the Cox model when TNM stage, age, ploidy, SPF, and tumour growth rate were analysed as covariates.     

A comparative study of DNA ploidy in 115 fresh-frozen breast carcinomas by image analysis versus flow cytometry.

BACKGROUND. Qualitative and quantitative analysis of cellular DNA content may be clinically useful in the prognostic evaluation of certain types of malignant tumors, including breast carcinoma. Flow cytometric (FCM) analysis has been the most frequently used procedure for DNA analysis, but it requires a reasonably large tissue sample. Computer-based image analysis (IA) now allows imprint, cytospin, and needle aspiration smear preparations and other small tissue samples to be used. METHODS. To resolve concern about the diagnostic efficacy of small tissue samples in the use of IA, the authors performed a comparative study of FCM analysis and IA using 115 fresh-frozen breast carcinomas. Feulgen-stained imprint preparations for IA and single-cell suspensions from the same fresh-frozen tissue for FCM analysis were used, and the respective histograms were compared. RESULTS. The results were concordant in 90.4% (104 of 115) of the cases, but 11 specimens yielded discordant data. IA provided histograms with a somewhat lower resolution and a relatively high coefficient of variation for the G0/G1 peak, thus rendering occasional tumors, which were near-diploid aneuploid by FCM analysis (four cases), not amenable to diagnosis by aneuploid characterization. In three additional cases, FCM analysis showed aneuploid hyperdiploid (two cases) and multiploid (one case) histograms, but IA only demonstrated a diploid peak. Conversely, in four other cases, aneuploid peaks were recognized only by IA. CONCLUSIONS. Computerized IA has significant advantages over FCM analysis, including lower cost, the ability to analyze very small specimens, the capability of detecting rare high ploidy cells, the capacity to classify cellular populations according to specific morphologic type, and the fact that no destructive enzyme or chemical digestion is required for specimen preparation, thereby preserving the integrity of fragile cells.