Prognostic value of flow cytophotometric DNA content analysis in single treatment stage IB-IIA squamous cell carcinoma of the cervix

S-Phase fraction, p53, and HER-2/neu status as predictors of nodal metastasis in early vulvar cancer

OBJECTIVE

Our aim was to determine the value of the S-phase fraction, p53, and HER-2/neu status as predictors of inguinal nodal metastasis in early vulvar cancer.

METHODS

The charts of 100 consecutive patients with invasive squamous cell cancer of the vulva were reviewed and a cohort of patients with clinical stage I or II disease treated primarily with radical surgery and inguinal node dissection was identified. Within this cohort, all node-positive patients were matched with node-negative controls by depth of invasion. Tumor from the 13 node-positive patients and 26 controls was then analyzed by flow cytometry and immunohistochemistry.

RESULTS

The median value of the S-phase fraction was higher in tumor from patients with inguinal nodal metastasis (median, 18.2; 25th-75th percentile: 13.9-28.3) than in node-negative patients (median, 8.9; 25th-75th percentile: 5.4-15.6) (P = 0.01). The presence of the HER-2/neu immunopositivity was also found to be associated with nodal metastasis (OR 4.05, 95% CI 1.0-16.6), but we found no evidence that DNA index or the presence of p53 immunopositivity was associated with nodal metastasis.

CONCLUSION

Early vulvar cancer patients with inguinal node metastasis have a significantly higher S-phase fraction and are more likely to have HER-2/neu immunopositivity when compared to those without nodal metastasis.

Immunogenetic and oncogenic properties of rat trophoblast cell lines

PROBLEM

The nature of major histocompatibility complex (MHC) antigen expression on rat placentas, trophoblast cell lines, and tumors derived from trophoblast cells was explored.

METHOD OF STUDY

Cytohistochemical and flow cytometric analysis and molecular techniques.

RESULTS

MHC antigen expression and genomic imprinting on the placenta and on trophoblast cells varies with the time of gestation and with the type of MHC antigen.

CONCLUSIONS

There is no correlation in trophoblast cells between class I expression and cell ploidy, on the one hand, and malignant potential, on the other hand. Genomic imprinting of class I antigens in the rat placenta is a quantitative phenomenon.

Prediction of radiotherapy response of cervical carcinoma through measurement of proliferation rate

Estimation of tumour proliferation may allow the design of individualised radiotherapy schedules to optimise response. This prospective study correlates the tumour proliferation rate of cervical carcinoma with response to conventional radiotherapy. The potential tumour cell doubling rate (Tpot) was estimated following flash labelling of the tumours in vivo using the DNA precursor, bromodeoxyuridine (BrdUrd); samples were analysed by flow cytometry. Tumour ploidy, DNA index and mitotic count were also assessed as was histological grade and type. Multiple biopsies from each tumour were obtained from 121 women. The median Tpot was 4.0 days, median S-phase duration 12.8 h and median adjusted labelling index 9.8%. Higher BrdUrd labelling was seen in patients who developed pelvic tumour recurrence following radiotherapy. This was the only biological/histological parameter with univariate and multivariate significance in relation to locoregional recurrence (P = 0.006 and P = 0.034 respectively). This study represents the first assessment of Tpot in relation to long-term response of cervical tumours treated by radiotherapy treatment. The association of high BrdUrd labelling and poor pelvic disease-free survival indicates the need for further research into the potential of radiotherapy schedule alteration to reflect tumour proliferation. The predictive value may be enhanced by combination with other biological parameters.

Proliferation measurements with flow cytometry Tpot in cancer of the uterine cervix: correlation between two laboratories and preliminary clinical results

PURPOSE

To assess the prognostic value of the pretreatment potential doubling time (Tpot) in carcinoma of the uterine cervix, relative to other established clinical factors.

METHODS AND MATERIALS

Fifty-two patients with cervical cancer were studied prospectively from March 1991 to October 1993. Pretreatment evaluation included examination under anesthesia and tumor biopsy 6 h following the intravenous administration of bromodeoxyuridine (200 mg). Tpot was determined by deriving the labeling index (LI) and S-phase synthesis time (Ts) using flow cytometry. Six patients were not evaluable and excluded. The remaining 46 patients (average age 55 years) were treated uniformly with radical radiation therapy. There were 39 squamous carcinomas and 7 adenocarcinomas. Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) stages were: Ib and IIa, 12 patients; IIb, 18 patients; III and IV, 16 patients. The median external beam dose was 50 Gy (range, 45-52.8 Gy) delivered in 25 fractions. The median intracavitary dose was 40 Gy (range. 25.5-40 Gy) delivered with a single line source to a point 2 cm lateral of the midline, with a mean dose rate of 0.71 Gy/h. The median overall treatment time was 45 days (range, 34-73 days). As of July 31, 1994, 12 patients had died of disease, and the average follow-up for alive patients was 1.4 years (range, 0.5-3.3 years).

RESULTS

There were 27 tumors with diploid deoxyribonucleic acid (DNA) content and 19 tumors were aneuploid. The median and mean Tpot for the 46 patients were 5.5 and 6.6 days, respectively [range, 2.0-25.6 days; coefficient of variation (CV), 74%]. For 25 patients where Tpot measurements were performed at two separate laboratories, there was a fair correlation (r = 0.74), but systematic differences were detected suggesting that the lack of agreement was not simply due to intratumoral variation. To date, 30 patients remained disease free, while 8 patients had pelvic failure and 9 patients developed distant metastases as the first failure site (1 patient developed both at the same time). In univariate analysis, the only significant prognostic factor for disease-free survival was tumor size (p = 0.004). A short Tpot (or high LI) and long overall treatment time (OTT) were weakly associated with poorer disease-free survival, although not statistically significant (1/Tpot, p = 0.14; LI, p = 0.23; OTT, p = 0.04). Age, FIGO stage, hemoglobin level, S-phase fraction, DNA ploidy, and Ts were not associated with disease-free survival. Multiple regression analysis was not performed because of the relatively small number of patients and short follow-up.

CONCLUSIONS

Tpot values determined with current techniques by different laboratories cannot be used interchangeably for the purpose of therapy decisions. Vigorous quality assurance and standardization of the laboratory procedures and analysis methods are important to reduce interlaboratory variation. In this uniformly treated group of patients with cancer of the uterine cervix, traditional clinical prognostic factors remain the most important. Preliminary data suggest that the flow cytometry-determined Tpot and labeling index predict for disease-free survival, although a larger number of patients with longer follow-up is required to assess the true prognostic significance of these assays and to determine if their effect is independent of other clinical factors.

Deoxyribonucleic acid ploidy and S-phase fraction are not significant prognostic factors for patients with cervical cancer

OBJECTIVE

Our purpose was to determine the usefulness of deoxyribonucleic acid ploidy and S-phase fraction as prognostic factors in patients with cervical cancer.

STUDY DESIGN

Paraffin-embedded tumor specimens were obtained from 123 patients with cervical cancer (mean age 51 years, range 21 to 87 years). The mean follow-up period was 6.4 years. Deoxyribonucleic acid ploidy and S-phase fraction were determined by flow cytometry.

RESULTS

A total of 119 patients were evaluable for deoxyribonucleic acid ploidy and 92 were evaluable for S-phase fraction. The overall rate of deoxyribonucleic acid aneuploidy was 60%, and the median S-phase fraction was 12.5%. Neither factor was significantly related to stage of disease. In univariate survival analyses patients with deoxyribonucleic acid aneuploid tumors had slightly better early survival than did patients with deoxyribonucleic acid diploid tumors (median survivals 2.7 and 1.4 years, respectively, p = 0.08 [Wilcoxon]), but the overall survival was not significantly different, p = 0.37 (log-rank). In multivariate analyses deoxyribonucleic acid ploidy was not a significant predictor of survival. S-phase fraction was not statistically significant in either analysis.

CONCLUSION

Deoxyribonucleic acid ploidy and S-phase fraction are not useful prognostic factors for patients with cervical cancer.

Expression of proliferation-associated antigens (PCNA, p120, p145) during the reentry of G0 cells into the cell cycle

Flow cytometric bivariate analysis was used to evaluate the expression of PCNA, p120, and p145 during the G0 reentry of CHO-K1 cells into the cell cycle. CHO-K1 cells were placed in a G0-like state using serum depletion and stimulated to reenter the cell cycle by replating into fresh, serum-containing medium. At discrete intervals after stimulation, replicate samples were stained for either PCNA, p120, or 145; stained for DNA (Coulter DNA-Prep); evaluated on the EPICS Profile I; and analyzed on the EPICS ELITE workstation. PCNA stained less than 10% of the G0 cells; in contrast, however, 30-35% of the G0 cells were positive for p120 and p145. Eight hours after stimulating G0 cells to reenter the cell cycle (during G0/G1), p120 reached 88% positivity, while p145 and PCNA were 63% and 30% positive, respectively. Cells in S phase (12 and 16 h following G0 stimulation) were greater than 90% positive for all three antigens. PCNA had the greatest change throughout the G0 reentry process, both in percentage positive and quantitatively (mean channel fluorescence). This report indicates that all three proliferation-associated antigens studied are differentially expressed during the reentry of G0 cells into the cell cycle. Furthermore, these antigens may be useful in the early detection of G0 recruitment.

The uses and limitations of DNA flow cytometry in stage IB or II cervical carcinoma

BACKGROUND

The role of flow cytometry in predicting prognosis for cervical carcinoma remains unclear.

METHODS

Flow cytometric analysis was performed on tissues, fixed in formaldehyde solution and embedded in paraffin, from 411 patients with Stage IB or II cervical carcinoma who had been treated with radical abdominal hysterectomy and bilateral pelvic lymphadenectomy.

RESULTS

DNA aneuploid-multiploid tumors were found in 37.5%, tetraploid in 4.6%, and diploid-peridiploid in 57.9%. Five-year recurrence-free survival rates of the three groups were 74.3%, 77.8%, and 76.4%, respectively (P > 0.05). DNA aneuploidy and DNA index (DI) of greater than 1.3 were highly correlated to parametria extension. In univariate analysis, pelvic lymph node metastases, stage, parametrial extension, depth of cervical stromal invasion, tumor size, and DI (1.3, 1.4, 1.5 as breakpoint) were significant prognostic factors. DNA ploidy, S-phase fraction, and S-G2M fraction were not significant. In multivariate analysis, DI of greater than 1.3, pelvic node metastases, clinical Stage II, and depth of stromal invasion greater than two-thirds of full cervical thickness were independent and significant variables. The prognostic index (PI), defined by the model, was able to categorize the patients into three distinct risk groups. The 5-year recurrence free survival rates of the low-, intermediate-, and high-risk groups were 89.5%, 73.0%, and 58.9%, respectively (P < 0.0001).

CONCLUSIONS

The prognostic value of the DI as a single variable is promising and warrants additional investigation to establish its appropriate use.

Measurement of cell kinetics in cervical tumours using bromodeoxyuridine

The pre-treatment cell kinetics of 120 cervical tumours were assessed following the in vivo labelling with the thymidine analogue Bromodeoxyuridine (BrdUrd). In 89% both static and temporal kinetic parameters could be measured. Through the analysis of multiple biopsies from each tumour marked intra tumour heterogeneity was demonstrated. The median values for the most highly labelled sample analysed for each tumour were; S-phase duration (Ts) 12.1 h, BrdUrd labelling index (CLI) 9.5% and potential tumour doubling time 4.4 days. There was a significant elevation in CLI, but no difference in Ts, between tumour and non-neoplastic cervical tissue. There was a significant elevation in CLI, advanced stage and large size tumours. Although a significant elevation in CLI was found in aneuploid tumours this is likely to represent the systemic bias of the calculation methods, with no difference being seen between aneuploid and diploid tumours when BrdUrd labelling was measured with-out reference to the nuclei DNA content. The majority of these patients were treated with radiotherapy and cell kinetic data will be correlated with treatment response when adequate follow up has been achieved.