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 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.     

Flow cytometric analysis of DNA content in human ovarian cancers

A total of 155 samples from 101 patients with ovarian cancer were investigated using flow cytometry to evaluate the DNA index and the percentage of cells in the various cell cycle phases. Thirty-four samples were DNA diploid tumours, while the other 121 were DNA aneuploid tumours. The DNA index was very stable in different sites and over time in the same patient. Tumour stage and ploidy were significantly associated: stages III and IV tumour stage were more likely to be DNA aneuploid. Patients with residual tumour size at first surgery greater than 2 cm had a significantly larger number of DNA aneuploid than DNA diploid tumours. The DNA index was also related to the degree of differentiation of the tumours. The percentage of cells in the S phase of the cell cycle was significantly higher in DNA aneuploid and in poorly differentiated tumours than DNA diploid and well differentiated tumours. Multivariate analysis using the Cox model showed that the DNA index and the percentage of cells in S phase were not independent prognostic variables in this study. Prospectively collected data should be accumulated before assigning the DNA index an important role as a biological prognostic factor in ovarian cancer.     

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.     

DNA ploidy and S-phase fraction as prognostic factors in patients with uveal melanomas.

In 96 patients with uveal malignant melanomas the tumours were investigated by DNA flow cytometry. Thirty-eight per cent of the melanomas were aneuploid. By univariate analysis significant correlations with survival were found for histological type, tumour size, DNA ploidy, evidence of ''blind eye'' and S-phase fraction. By multivariate analysis, significant prognostic variables were found to be histological type (P = 0.0008), tumour size (P < 0.0001) and DNA ploidy (P = 0.0038). Evidence of ''blind eye'' was not significantly correlated with survival after adjustments for the other variables mentioned above. The S-phase fraction could be estimated in all 60 diploid tumours and in 12 of 36 aneuploid melanomas. By univariate analysis this variable was found to be a significant prognostic factor, but did not remain so after adjustment for ploidy, histological type and tumor size. We further conclude that patients with small DNA diploid uveal melanomas of spindle cell type have a rather favourable prognosis.     

鼻咽癌新鲜肿瘤组织DNA倍体性与预后的关系

背景与目的:因肿瘤有生物学异质性,部分肿瘤的预后和TNM分期并不符合;寻找有效的生物学预后指标作为临床分期的补充,可为今后鼻咽癌的个体化治疗提供一个新的依据.本研究探讨初治鼻咽癌患者新鲜肿瘤组织细胞的DNA倍体性与疗效、预后的关系.方法:1999年1月至2000年2月,53例初治鼻咽癌患者进入本研究,其中单纯放疗32例,另21例患者于放疗第4周接受了一个疗程的PF方案化疗.患者治疗前均活检取新鲜肿瘤组织,用流式细胞仪进行DNA倍体检测.结果:53例患者中,二倍体32例(60.4%),异倍体21例(39.6%).不同倍体组患者的年龄、性别、临床分期、N分期、化疗与否的差异无统计学意义(P=0.695、0.657、0.088、0.972和0.335).全组患者中位随访时间73个月(12～84个月).全组5年总生存率65.61%,其中二倍体组为80.92%,异倍体组为42.86%(P=0.002);5年无远处转移生存率二倍体组为84.26%,异倍体组为44.53%(P=0.003);5年无复发生存率二倍体组为92.59%,异倍体组为72.65%(P=0.118).单因素分析结果显示,临床分期是无复发生存率的影响因素,DNA倍体性、临床分期和T分期是总生存率和无远处转移生存率的影响因素.多因素分析结果显示,与总生存率相关的独立预后因素为DNA倍体性(P=0.020)和临床分期(P=0.007),与无转移生存率相关的预后因素亦为DNA倍体性(P=0.017)和临床分期(P=0.011).结论:采用流式细胞术检测新鲜组织细胞的DNA倍体性和临床分期一样可以预测鼻咽癌患者的预后;DNA异倍体患者比二倍体患者更容易出现远处转移而导致治疗失败.     

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.     

Heterogeneity in renal cell carcinoma and its impact no prognosis--a flow cytometric study.

In the process of tumour progression genetic instability is the basis for the evolution of tumour cell clones with various genotypic and phenotypic characteristics causing heterogeneity. Renal cell carcinoma has a long prediagnostic growth period, which increases the probability of clonal evolution. We have studied 200 consecutive renal cell carcinomas, addressing the interrelationship between intratumour heterogeneity and clinicopathological factors. DNA ploidy patterns were analysed in multiple samples from each tumour using flow cytometry and compared with clinical stage, tumour invasion, metastatic rate and survival. Eighty-five of 192 evaluable tumours (44%) were homogeneous concerning DNA ploidy (62% diploid, 38% aneuploid). Among 107 heterogeneous tumours a majority (79%) contained aneuploid as well as diploid cell clones. Homogeneously diploid tumours had a lower incidence of local tumour spread compared with tumours with aneuploid cell clones (P < or = 0.001), but the frequency of distant metastasis at time of diagnosis was similar. The presence of aneuploidy in at least one sample from a tumour was a significant adverse prognostic factor (P < 0.001), whereas the degree of heterogeneity had no influence on survival. The frequent heterogeneity demonstrated indicates that multiple samples must be investigated to evaluate properly the malignant character of renal cell carcinoma.     

Effect of tamoxifen upon cell DNA analysis by flow cytometry in primary carcinoma of the breast

The effect of tamoxifen upon cellular DNA ploidy in carcinoma of the breast was assessed by flow cytometry (FCM), in a prospective group of 77 patients with primary operable disease. Each had a needle biopsy at the outpatient visit for diagnosis and FCM analysis, and definitive surgery was performed a median of 8 days later. Forty received tamoxifen during this period - 40 mg qds loading dose for 24 h, followed by 20 mg daily until the day of operation: 37 patients received no therapy. The DNA histogram from the needle biopsy was compared with that obtained from the resected tumour for each individual. There was little change between the pair of histograms from tumours from the untreated patients. In those who had received tamoxifen the most consistent effect was a marked reduction in the magnitude of the 'tetraploid' peak in tetraploid or near-tetraploid tumours with DNA indices 1.8-2.0. There was little change in diploid or 'other DNA-aneuploid' tumours. In tetraploid tumours (DNA index of 2.0) the percentage of nuclei in the diploid S phase was significantly related to the percentage of nuclei in the diploid G2 + M/tetraploid G1 peak (P less than 0.003, unpaired t test). These data suggest that an effect of tamoxifen can be demonstrated by FCM upon tumours exhibiting a tetraploid or near-tetraploid DNA content. It is possible that tetraploid or near-tetraploid human mammary tumours may be a distinct group of endocrine responsive tumours within the overall group of aneuploid tumours, and that the majority are probably derived from the diploid population rather than being a true aneuploid population.     

Tumour cell kinetics as a prognostic factor in squamous cell carcinoma of the cervix treated with radiotherapy.

PURPOSE: Proliferative rate and DNA ploidy status were evaluated by flow cytometry in cervical cancer patients, prior to radiotherapy, to assess their importance as prognostic factors to predict survival rates. MATERIAL AND METHODS: Between 1987 and 1995, a total of 260 patients with squamous cell carcinoma (SCC) of the cervix, FIGO stages IB-IIIB were analysed. Tumour samples were incubated with bromodeoxyuridine (BrdUrd) in vitro to measure their total labelling index (totLI) and LI (totLI for diploid and anLI for aneuploid tumours). Proliferation was also assessed by S-phase fraction (SPF) analysis of the DNA profile. Patients had intracavitary therapy (three applications, each of 16 Gy to point A) and XRT of 40-50 Gy given over 4-5 weeks. RESULTS: The cervical tumours were characterized by a high proliferation rate which varied within each clinical stage of disease. The totLI ranged from 1.1 to 33.1% with median value of 9.6% whilst the LI ranged from 1.1 to 37.1% with a median value of 10.9%. Univariate analysis identified patient's age (cut-offpoint < or = 50&greater; years) and to a lesser extent proliferation (cut-off point, median totLI=9.6%) as significant prognostic factors for 5-year survival. The median survival time for younger patients ( < or = 50 years) with tumours of low proliferation (totLI < or = 9.6%) tumours was 17.5 months compared with 56 months in the faster proliferating tumours (P=0.0354). In the older patient sub-group, proliferation rate had no influence on survival. The median LI value was not a useful parameter in survival. Cox multivariate analysis showed that patient age ( < or = 50 years) and low proliferation of the tumour cells (totLI < or = 9.6) were unfavourable prognostic factors for cervical cancers treated with radiotherapy. DNA ploidy was not significant in this series. CONCLUSIONS: These data suggest that further improvements in therapy might be gained by selection of alternative treatments strategies such as neoadjuvant chemotherapy or radiation sensitizers in younger patients with more slowly proliferating tumours.     

The prognostic significance of DNA flow cytometry in breast cancer: results from 881 patients treated in a single centre.

In this single-centre study of 881 patients, S-phase fraction (SPF) was shown to be a significant prognostic marker in terms of overall survival (OS), relapse-free survival (RFS) and survival after relapse (SAR). Further, SPF had independent prognostic significance when considering a range of other clinicopathological variables, namely tumour grade and stage, nodal status, patient age, tumour size, menstrual status and treatment details. For OS and RFS, SPF was the second strongest predictor of the clinical course of the disease after nodal status, and for SAR it was the strongest prognostic marker. SPF correlated positively with histological grade but was the stronger predictor of survival. The distribution of SPF values was markedly different for the two ploidy classes of tumour, with DNA aneuploid tumours having a significantly higher average SPF. However, SPF retained its independent prognostic ability when DNA diploid and aneuploid tumours were analysed separately, DNA ploidy itself also proved to be an independent prognostic marker but the survival difference between the two ploidy classes was much less than that seen for different levels of SPF. Tumours with several DNA aneuploid populations (multiploid tumours) tended to have a worse prognosis than other aneuploid tumours but this trend did not reach statistical significance. In this and other studies from this centre, SPF has proved to be a robust predictor of clinical outcome in carcinoma of the breast.     

Predicting outcome for patients with node negative breast cancer: a comparative study of the value of flow cytometry and cell image analysis for determination of DNA ploidy.

This study was aimed at determining whether tumour DNA content measured by cell image analysis could provide additional prognostic information when compared to that provided by flow cytometry. Sections cut from paraffin blocks of tumours from 101 patients with node negative breast cancer were analysed by both methods and the results related to other prognostic variables and to patient relapse and overall survival. DNA ploidy measured by flow cytometry classified 46 tumours as diploid and 55 as aneuploid, whereas by cell image analysis 30 were diploid and 71 aneuploid (P less than 0.002). There were 20 tumours with discrepancies between the two methods; 18 of these were tumours with only one peak in flow analysis, but determined to be aneuploid with image analysis. DNA content as measured by both methods was significant for predicting relapse and survival by log-rank test, as were tumour histological grade, c-erbB-2 expression and tumour size. Multivariate analysis showed DNA ploidy measured by flow cytometry to be the only variable of independent significance (P less than 0.02) for both relapse and overall survival. Compared with cell image analysis, flow cytometry demonstrated a significantly higher proportion of diploid tumours, which may be related to differences in the internal standards applied to each method. We suggest that cell image analysis techniques can provide more sensitive information on the DNA content of tumour cells by direct measurement of nuclear DNA density of both normal lymphocytes and tumour cells in the same section. However, although image analysis appears to be more sensitive than flow cytometry in detecting DNA aneuploidy, the image technique appears to lack the specificity of flow cytometry in correlation with clinical outcome.     

Flow cytofluorometric evidence for the differential radioresponsiveness of aneuploid and diploid cervix tumours

We are presently involved in a prospective study of the relationship between DNA content profiles, and their changes during treatment, determined by flow cytofluorometry, and patient prognosis and response to therapy for cancer of the uterine cervix. To date, 348 patients have been included in the study over a 54-month period. Data on these patients have shown that DNA aneuploid tumours are significantly more radioresponsive than diploid cervix tumours. Analysis of the data on 213 patients with a minimum follow-up time of 15 months has, however, failed to show an overall more favourable prognosis conferred by tumour DNA aneuploidy. Analysis of the relationship between clinical stage and disease state and tumour DNA ploidy, however, suggests that aneuploid tumours metastasize to distant sites at an earlier stage of the disease than diploid tumours and local recurrence rates for diploid tumours, in late stage disease, are double those for aneuploid tumours. Improved staining procedures, and instrument modification, has also shown that cervix tumour heterogeneity is of considerably greater frequency than at first appeared to be the case (approximately 75% of DNA aneuploid tumours show heterogeneity.     

Prognostic value of ploidy of primary tumour and nodal secondaries in colorectal cancers

Tumour ploidy is of prognostic value in colorectal cancer, DNA aneuploid tumours having a worse outlook. Nearly all studies have concentrated on the DNA content of the primary tumour. We have examined the ploidy of the primary tumour and its lymph node metastases in 71 cases of Dukes' stage C disease, to see whether this provides greater prognostic information than the primary alone. Analysis was performed using formalin-fixed, paraffin-embedded tumour sections. Ploidy of primary and metastases was different in 20 cases (28%), aneuploid nodes being seen with diploid primaries and vice versa. Ploidy of both the primary (χ² = 4.86, P = 0.03) and secondary (χ² = 4.86, P = 0.03) tumours predicted survival in univariate analysis. Combining the ploidy of primary and nodes, three prognostic groups could be defined — diploid primaries with diploid metastases (hazard relative to both aneuploid, 0.36) had significantly better survival than cases where the ploidy of the primary and nodes were mixed (relative hazard 0.47–0.56), which did better than cases with aneuploid primary and nodes. This study demonstrates that ploidy variation between primary and secondary tumours is common, and better prognostic information may be gained by studying both.     

Ploidy as a prognostic indicator in end stage squamous cell carcinoma of the head and neck region treated with cisplatinum

We measured tumour cellular DNA in 102 patients entered into two phase III trials of chemotherapy for end stage squamous carcinoma of the head and neck. The median survival of untreated patients with aneuploid tumours was 55 days compared with 224 days for patients treated with cisplatinum. This difference was highly significant. In contrast the median survival of untreated patients with diploid tumours was 74 days compared with 118 days for treated patients. Although this difference is statistically significant, the increased survival of 6 weeks is of no clinical benefit compared with the prolongation of survival of 6 months in patients with aneuploid tumours. Multivariate analysis showed that the significant predictors of survival were Karnofsky status, response to chemotherapy and ploidy.     

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.     

Prognostic value of DNA flow cytometry in stomach cancer: a 5-year prospective study

The role of DNA flow cytometry in the prediction of prognosis for patients with stomach cancer remains to be defined. Thus we studied prospectively the role of DNA flow cytometry as a prognosis indicator in stomach cancer patients in a high-incidence area. Between November 1990 and December 1992, primary stomach cancer tissues were obtained from the surgical specimens from 217 patients (148 male, 69 female). DNA flow cytometric analyses of DNA ploidy and S-phase fraction were performed and the results were correlated with patient survival. The median age of the patients was 55 years (range 24-78). Aneuploid cell population was found in 114 of 217 samples (53%). Tumour S-phase fraction was obtained in 96 of 103 diploid tumours (93%) and 61 of 114 aneuploid tumours (54%). After median follow-up of 66.1 months, the patients with tumours with an S-phase fraction over 17% had significantly worse survival rates than patients with tumours with S-phase fractions of lower than 8% or 8-17% (45% vs 59% and 63% of patients surviving, P = 0.007). Tumour ploidy status did not correlate with patient survival. Multivariate analyses showed that the TNM stage remained the most important prognostic indicator. The tumour S-phase fraction was also an independent prognostic indicator (relative risk 2.300, 95% CI, 1.252-4.223). Tumour S-phase fraction obtained by DNA flow cytometry is an independent prognostic indicator for the survival of the patients with stomach cancer.     

Tumour DNA ploidy as an independent prognostic factor in breast cancer

We determined nuclear DNA content from 308 archival paraffin-embedded malignant breast tumours and evaluated the survival of the patients by univariate and multivariate statistical analyses. The overall 8-year survival rate of stage I-III breast cancer patients was 74.3% in DNA-diploid and 51.2% in DNA-aneuploid tumours (P less than 0.0001). DNA ploidy had prognostic significance in both node-negative and node-positive breast cancer, primarily in cases with steroid receptor-positive tumours. In a Cox multivariate analysis DNA ploidy (P = 0.001), primary tumour size (P = 0.0007), nodal status (P = 0.04) and the content of progesterone receptors (P = 0.0008) emerged as significant independent prognostic factors, whereas oestrogen receptor status, age and menopausal status of the patients had no significant independent prognostic value. If the histological grade of ductal carcinomas was also included in the Cox model, both grade and DNA ploidy had independent prognostic effect. In conclusion, our results indicate that the analysis of DNA ploidy is a useful adjunct in the assessment of prognosis for breast cancer patients.     

The influence of tumour cell DNA content on survival in colorectal cancer: a detailed analysis

We have investigated the influence of tumour cell DNA content (ploidy) on survival of 416 patients undergoing excisional surgery for colorectal cancer. Two hundred and eleven (51%) tumours had an abnormal DNA content (aneuploid or tetraploid). There was no correlation between ploidy status, sex, age and pathological stage, histological grade, tumour site, local tumour extension or assessment of curability. Patients with tumours with an abnormal DNA content had a poorer survival 68/211 (32%) than patients with near normal (diploid) DNA content 88/205 (43%) (test statistic 5.0, P = 0.02). The patient subgroups in which DNA content exerted an influence on survival were: stage B tumours (P = 0.0058), moderately differentiated tumours (P = 0.004), rectal tumours (P = 0.02), and mobile tumours (P = 0.02). Multivariant analysis showed that pathological stage, local tumour extension and DNA ploidy were all independent prognostic indicators whereas histological grade, tumour site and assessment of 'curability' were not. The influence of pathological stage, however, was much greater than that of local tumor extension or DNA ploidy. Tumour cell DNA content together with pathological stage and local tumour extension may be used in a prognostic index and may be important in planning adjuvant therapy.     

Prognostic significance of DNA ploidy, S-phase fraction, and P-glycoprotein expression in colorectal cancer

BACKGROUND AND OBJECTIVES: Parameters that allow prediction of the disease course in colorectal cancer would aid the development of improved treatment strategies. For this reason, we evaluated the prognostic value of flow cytometric DNA ploidy and S-phase fraction (SPF) and P-glycoprotein (Pgp) expression in this type of tumor. METHODS: The prognostic significance of DNA ploidy, SPF, and Pgp expression on paraffin-embedded sections from 107 patients with colorectal carcinoma was determined. The mean follow-up was 36.6 months (range = 3-72 months). DNA ploidy and SPF were evaluated by flow cytometry and Pgp by immunohistochemistry using monoclonal antibody C219. The Cox regression model was used to adjust for several clinical and pathologic covariates. RESULTS: Of the 107 carcinomas examined, 44 (41.1%) were classified as DNA diploid and 63 (58.9%) as DNA aneuploid. DNA ploidy pattern was significantly related to tumor site (P = 0.010), tumor stage (P = 0.016), and vascular invasion (P = 0.015) but not to other clinicopathologic variables. Patients with DNA diploid tumors showed a better survival rate than did those with aneuploid tumors. After stage IV disease was excluded, patients with diploid tumors also presented a better disease-free and overall survival than did patients with aneuploid tumors. Mean SPF of the whole series was 13.5% (median = 11.3%, range = 1.4%-29.9%). Aneuploid tumors had a higher median SPF than did diploid tumors (17 vs. 6.2; P = 0.0001). SPF was only related significantly with tumor location (P = 0.026). In the multivariate analysis, SPF was a significant independent prognostic factor for overall survival (P = 0.01). When stage IV was excluded, SPF was also an independent prognostic variable for both disease-free (P = 0. 02) and overall (P = 0.01) survival. Of 107 tumors, 61 (57%) were positive for Pgp expression, but no relation was found between this and other clinicopathologic parameters. Pgp expression had no influence on survival. CONCLUSIONS: Our results suggest that flow cytometric DNA ploidy and SPF are significant and independent prognostic factors in patients with colorectal carcinoma, whereas Pgp expression is not.