Long-term survival and DNA ploidy in advanced epithelial ovarian cancer

P53 Expression, Dna Ploidy and Mitotic Index as Prognostic Factors in Patients with Epithelial Ovarian Carcinoma

Aims and Background

Biological variables linked to genomic instability were examined and related to survival in 52 patients affected by ovarian carcinoma and nine patients with low malignant potential tumors (LMP).

Methods

DNA ploidy was measured by image cytometry in isolated neoplastic cells; the mitotic index was measured in Feulgen-toluidine blue-stained sections and p53 was investigated by immunohistochemistry.

Results

Twenty-five tumors (4 LMP) were peridiploid (ploidy <2.25c), 22 tumors (4 LMP) were hyperdiploid (2.25c>ploidy<2.9c) and 14 (1 LMP) had high ploidy (≥2.9c). Ml ranged from 0.3 to 24.2 with a mean of 1.8 for LMP and 6.8 for carcinomas (P <0.001). Widespread p53 overexpression was detected in 49% of carcinomas and in none of the LMP tumors.

Conclusions

Survival analysis performed in patients with carcinomas indicated that, of the examined biological variables, only Ml was moderately associated with survival in a subgroup of early-stage patients.

Distinct patterns of structural and numerical chromosomal instability characterize sporadic ovarian cancer

Sporadic ovarian cancer is a particularly aggressive tumor characterized by highly abnormal karyotypes exhibiting many features of genomic instability. More complex genomic changes in tumors arise as a consequence of chromosomal instability (CIN), which can generate both numerical [(N)-CIN] and structural chromosomal instability [(S)-CIN]. In this study, molecular cytogenetic analysis was used to evaluate the relative levels of both (N)-CIN and (S)-CIN. Six tumors had a near-diploid chromosome number, two were near-tetraploid, and two were near-triploid. (N)-CIN levels increased as a function of overall tumor genomic content, with near-diploid tumors exhibiting numerical instability indices ranging from 7.0 to 21.0 and near-tetraploid and triploid tumors exhibiting instability indices ranging from 24.9 to 54.9. In contrast, the extent of (S)-CIN was generally more evident in the diploid tumors compared with the near-tetraploid tumors. To determine whether the associated chromosomal constitution and/or ploidy changes were influenced by mitotic segregation errors, centrosome analyses were performed on all 10 tumors. The near-diploid tumors, with the lowest numerical change, were observed to possess fewer cells with centrosome abnormalities (5.5% to 14.0%), whereas the near-tetraploid tumors possessed much higher levels of (N)-CIN and were characterized by a trend of elevating percentages of cells with abnormal centrosomes (16.0% to 20.5%). These observations suggest that two distinct processes governing genome stability may be disrupted in ovarian cancer: those that impact on numerical segregation and ploidy of chromosomes and those that affect the fidelity of DNA repair and lead to structural aberrations.

Multivariate analysis of the prognostic significance of DNA-ploidy and S-phase fraction in ovarian cancer determined by flow cytometry following detection of cytokeratin-labeled tumor cells

OBJECTIVE

The outcome of patients with advanced ovarian cancer is poor despite aggressive therapy including surgery and multiagent chemotherapy. Valid prognostic factors are necessary to estimate the course of the disease and to define biologically similar subgroups for analysis of therapeutic efficacy.

METHODS

This study is the first published prospective study concerning the prognostic significance of DNA-ploidy and S-phase fraction in ovarian cancer following enrichment of tumor cells by cytokeratin labeling. Epithelial cells were labeled by FITC-conjugated cytokeratin antibody (CK 5, 6, 8, and 17) prior to flow cytometric cell cycle analysis in 129 fresh specimens of primary ovarian cancer.

RESULTS

Recurrence-free survival of patients with DNA-diploid primary ovarian cancer was significantly better compared to that of patients with DNA-aneuploid tumors in univariate analysis (47% vs 18%, P = 0.01). The tumor-dependent overall survival of patients with DNA-diploid tumors was 57% compared to 30% with DNA-aneuploid tumors (P = 0.04). In FIGO stage III ovarian cancer DNA-ploidy, optimized by cytokeratin gating for tumor cells, achieved independent prognostic significance. No significance was found for S-phase fraction. However, despite convincing methodological advantages in the detection of DNA-aneuploid subpopulations the clinical significance of cytokeratin gating of epithelial cells was only marginal.

CONCLUSION

DNA-ploidy has been shown to be as powerful or even more so in comparison to postoperative residual tumor in multivariate analysis for predicting clinical outcome in advanced ovarian cancer. Thus, determination of DNA-ploidy should be introduced to currently recruiting phase III studies for therapy of ovarian cancer for better definition of prognostic subgroups.

Are DNA ploidy and epidermal growth factor receptor prognostic factors for untreated ovarian cancer? A prospective study

To identify prognostic factors for untreated ovarian cancer, DNA ploidy, proliferative index (P.I.) and epidermal growth factor receptor (EGFR) expression were analyzed in a prospective series of 40 patients with ovarian cancer and 7 patients with borderline malignant ovarian tumor followed up for 5 years or more (median, 77 months). The frequency of aneuploid cells was 53.8% (21/39) in ovarian cancer and 14.3% (1/7) in borderline malignancy. There was no significant association between DNA ploidy and the clinicopathologic findings, in which aneuploid ovarian cancer was more common among advanced tumors. The S-phase fraction and P.I. value were higher in the patients with aneuploid tumors (p = 0.076). EGFR expression was detected in 76.9% (30/39) of ovarian cancers and 42.9% (3/7) of borderline malignant ovarian tumors, and the mean EGFR level was 5.8 +/- 12.1 (range: 0-49.5) and 28.3 +/- 71.1 (range: 0-189.4) fmol/mg protein, respectively. There was no correlation between EGFR expression and DNA ploidy, P.I., and clinicopathologic findings analyzed. The 5-year survival rate in patients with aneuploid tumors was significantly worse in patients with ovarian cancer (p = 0.0165, log-rank test). No significant relationship was shown between P.I., EGFR expression, and 5-year survival. Cox multivariate analysis showed that DNA ploidy, P.I., and EGFR expression are not associated with the risk of death (p = 0.5917, p = 0.9924, and p = 0.6840, respectively), although clinical stage shows a significant relationship (p = 0.0027). Our data showed that DNA ploidy is significantly related to the prognosis by univariate analysis, but DNA ploidy, P.I., and EGFR expression were not independent prognostic factors for the untreated ovarian cancer.

Prognostic significance of DNA content and S-phase fraction in epithelial ovarian carcinomas analyzed by image cytometry

The objective of this study was to evaluate the prognostic significance of DNA ploidy and S-phase fraction (SPF) in epithelial ovarian carcinomas analyzed by image cytometry. Frozen tissue of 103 epithelial ovarian carcinomas was analyzed for DNA ploidy and SPF with a Cell Analysis System Image Analyser (CAS 200, Becton-Dickinson) and correlations with clinical and histomorphologic factors and time to progression and overall survival were evaluated by univariate and multivariable analysis. Fifty-four percent of the ovarian carcinomas were found to be diploid, 38% aneuploid, and 8% tetraploid. The S-phase fraction was low (<5%) in 27%, intermediate (5-14.5%) in 47%, and high (>/=14.5%) in 26% of the patients. By univariate analysis overall survival and time to progression were significantly correlated with the S-phase fraction (P = 0.003 and P = 0.003), but not with DNA ploidy (P = 0. 31 and P = 0.51). A DNA index > 1.4 was correlated with poor outcome but the result did not achieve formal statistical significance (P = 0.08 and P = 0.12). A high SPF was a strong predictor of early recurrence, while a low SPF identified patients with a favorable long-term outcome. Other significant predictors of survival were FIGO stage, grade of differentiation, presence of distant metastasis, residual tumor, lymph node metastasis, and patient age. In multivariable statistical analysis only FIGO stage, histologic grade, and residual tumor after surgery were independent predictors of overall survival and time to progression.