Comparison of static and flow cytofluorometry for estimation of DNA index and S-phase fraction in fresh and paraffin-embedded breast carcinoma tissue

Reliability of DNA cytometric S-phase analysis in surgical biopsies: assessment of systematic and sampling errors and comparison between results obtained by image and flow cytometry

Three major parameters in DNA histograms that contribute to the reliability of S-phase analysis were evaluated. These parameters are (1) the extent of background in relation to the amount of S-phase cells (and the validity of its subtraction), (2) the size of the "free" S-phase range (S(free)), and (3) the sampling error of cell counting. Tests in histograms obtained from surgical biopsies by flow cytometry (FCM) showed that the background subtraction is reliable if the found S-phase fraction is higher than the fraction of background events in the histogram range of the cell population. The size of S(free) was determined in computer-generated test histograms as a function of variables such as the coefficient of variation (CV) and the DNA index (DI). To calculate the sampling error of cell counting above background and in S(free), a model was developed that was validated by experimental data. This error can serve as an indicator of the uncertainty in S-phase analysis. The poor correlation found between %S values measured by image cytometry (ICM) and FCM in surgical biopsies was assigned to high uncertainty by low cell numbers in ICM histograms. A method is proposed to estimate quantitatively the reliability of S-phase analysis that can facilitate the interpretation of results.

Endometrial stromal sarcoma of the uterus: a clinicopathologic, DNA flow cytometric, p53, and mdm-2 analysis of 17 cases

Seventeen patients with endometrial stromal sarcoma (ESS) diagnosed between 1970 and 1996 were evaluated according to DNA ploidy, S-phase fraction (SPF), p53, and mdm-2 expression, as well as traditional clinical and pathologic prognostic factors, such as tumor stage, grade, and mitotic index. DNA flow cytometric analysis and immunohistochemical staining for p53 and mdm-2 were performed on paraffin-embedded archival tissue from the uterine tumors. Flow cytometric DNA histograms were obtained from 16 patients. The patients ranged in age from 41 to 78 years (median, 57 years). Seven (41%) patients were premenopausal. Thirteen low-grade ESS were DNA diploid and had a low SPF. Of these, two overexpressed p53, while only one was mdm-2 positive. Among the four high-grade ESS we found one (25%) DNA diploid tumor and three (75%) DNA aneuploid tumors. Two (50%) had an SPF greater than 10%, three (75%) were p53-positive, and two (50%) overexpressed mdm-2. During the observation period, nine (53%) patients (five with low-grade and four with high-grade tumors) died of disease. The 5-year survival rate for patients with low-grade ESS was 74%, while all four patients with high-grade ESS died of disease within 14 months of diagnosis. Using the log-rank test, we found a significant correlation between survival and tumor grade (P = 0.007), DNA ploidy (P = 0.026), SPF (P = 0.048), and FIGO surgical stage (P = 0.026). In conclusion, we found that tumor grade was a strong predictor of clinical outcome in ESS. In addition, a worse prognosis was found for those ESS patients with advanced disease, DNA aneuploidy, and a high SPF. There was no difference between the recurrent and nonrecurrent group of early stage (surgical stage I), low-grade ESS with regard to clinicopathological features, DNA ploidy, SPF, p53, and mdm-2 expression. All patients with high-grade ESS died of disease within 14 months of diagnosis. In contrast, only three of the 11 patients with early stage, low-grade ESS died of disease.

Adenosarcoma of the uterus: a clinicopathologic, DNA flow cytometric, p53 and mdm-2 analysis of 11 cases

Eleven patients with uterine adenosarcoma diagnosed between 1970 and 1995 were evaluated according to DNA ploidy, S-phase fraction, p53 and mdm-2 expression, and traditional clinical and pathological prognostic factors, such as tumor stage, grade and mitotic index. DNA flow cytometric analysis and immunohistochemical staining for p53 and mdm-2 were performed on paraffin-embedded archival tissue from the uterine tumors. The patients ranged in age from 41 to 90 years (median, 76 years). Only one patient was premenopausal at the time of diagnosis and five (45%) were nulliparous. One patient had received previous pelvic irradiation for anal squamous carcinoma. Six of the tumors (55%) were pure adenosarcoma and five (45%) were adenosarcoma with sarcomatous overgrowth. Nine patients had a stage I tumor and two had a stage II tumor. Among the six adenosarcomas we found three DNA diploid tumors, two DNA aneuploid tumors, and one DNA multiploid tumor. All adenosarcomas had an S-phase fraction less than 10%, except one that was not assessable. None was p53 positive and only one overexpressed mdm-2. All five adenosarcomas with sarcomatous overgrowth were DNA aneuploid, three (60%) had an S-phase fraction > 10%, two (40%) were p53 positive, and one (20%) overexpressed mdm-2. Five of the eleven patients suffered recurrences, and three (60%) of these developed lung metastases. During the observation period four (36%) patients (2 adenosarcomas and 2 adenosarcoma with sarcomatous overgrowth) died of disease, three patients died of intercurrent disease without recurrence, and the remaining four are alive with no evidence of disease. The overall five-year survival rate for all stages was 69%; for patients with AS it was 80%, while for those with adenosarcoma with sarcomatous overgrowth it was 50%. There were no variables which correlated with survival. In conclusion, we found hat the typical adenosarcoma had a tendency to be of low stage, have a lower mitotic rate and an S-phase fraction <10%. On the other hand, adenosarcomas with sarcomatous overgrowth were of high grade, had a high mitotic rate, and were DNA aneuploid with an S-phase fraction >10%. None of the variables studied correlated with survival. Tumors that were p53-positive or overexpressed mdm-2 did not behave worse than their negative counterpart. All patients who recurred with distant metastases died of disease.

Leiomyosarcoma of the uterus: A clinicopathologic, DNA flow cytometric, p53, and mdm-2 analysis of 49 cases

AIM

The authors analyzed in a retrospective manner the prognostic significance of p53 and mdm-2 expression, DNA ploidy, S-phase fraction (SPF), and traditional clinical and pathological prognostic factors in patients with uterine leiomyosarcomas.

MATERIAL

Forty-nine patients were diagnosed with uterine leiomyosarcoma (25 stage I, 4 stage II, 8 stage III, and 12 stage IV). DNA flow cytometric analysis and immunohistochemical staining for p53 and mdm-2 were performed on paraffin-embedded archival tissue from the uterine tumors.

RESULTS

Of the 49 patients, 35 (71%) died of disease and 2 died of intercurrent disease. The 5-year survival rate was 33%. FIGO surgical stage, DNA ploidy, SPF, mitotic index, cellular atypia, and tumor grade obtained significance (P < 0.05) in a univariate survival analysis of the leiomyosarcomas. In a multivariate analysis with survival as the end point, stage was found to be the most important factor (P = 0.007); DNA ploidy (P = 0. 045) and SPF (P = 0.041) also had independent prognostic significance. For FIGO stage I tumors, DNA ploidy (P = 0.04) and tumor grade (P = 0.01) were statistically significant in a univariate analysis, while only grade had independent prognostic significance (P = 0.01) in a multivariate analysis. In a univariate analysis including only FIGO stage I and II tumors with disease-free survival as the end point, p53 overexpression (P = 0.0016), DNA ploidy (P = 0.042), and tumor grade (P = 0.008) obtained significance. In a multivariate analysis, only p53 had independent statistical significance (P = 0.01). All p53 immunopositive stage I-II tumors recurred within 28 months from diagnosis.

CONCLUSION

This study found that stage represents the most important prognostic factor for uterine leiomyosarcomas. DNA ploidy and SPF had independent prognostic value. DNA flow cytometry is useful in gaining additional prognostic information. In stage I patients, tumor grade gives significant information regarding clinical outcome. In addition, p53 overexpression may predict a higher risk of recurrence in early stage leiomyosarcomas.

Malignant mixed Müllerian tumors of the uterus: a clinicopathologic, DNA flow cytometric, p53, and mdm-2 analysis of 44 cases

AIM

The authors retrospectively analyzed the prognostic significance of p53, mdm-2, DNA ploidy, S-phase fraction (SPF), and traditional clinical and pathologic factors in patients with malignant mixed Müllerian tumors (MMMT) of the uterus.

METHODS

Between 1970 and 1995, 44 uterine tumors were diagnosed as MMMT (21 stage I, 2 stage II, 10 stage III, and 11 stage IV). Thirty-two were homologous type and 12 were heterologous type. DNA flow cytometry and immunohistochemical analysis for p53 and mdm-2 overexpression were performed on paraffin-embedded archival tissue.

RESULTS

68% of the tumors were nondiploid and 61% had an SPF greater than 10%. Sixty-one percent overexpressed p53 and 25% were mdm-2-positive. Furthermore, 91% of the tumors had a mitotic count greater than 10/10 hpf and 95% had high-grade cytologic atypia. Twenty-seven (61%) patients died of tumor and 6 (14%) died of intercurrent disease. Eleven (25%) patients are alive with no evidence of disease. The median follow-up for patients still alive was 59 months (range, 28-178 months). The overall 5-year survival rate was 38%. In a univariate analysis that included stage, histologic type, DNA ploidy, SPF, p53, mdm-2, mitotic index, and age, and with survival as the end point, only stage reached statistically prognostic significance.

CONCLUSION

The majority of the tumors had obvious signs of aggressiveness such as high grade, high mitotic count, nondiploid pattern, high SPF, and overexpression of p53. This study found that stage is the most important prognostic factor for survival in MMMTs of the uterus.

Flow cytometric DNA-heterogeneity in paraffin-embedded endometrial cancer

To evaluate the degree of intratumoral DNA ploidy heterogeneity in endometrial carcinoma, the authors examined curettage specimens from 30 patients with clinical stage I and II endometrial carcinoma. The curettage material was obtained before the onset of treatment. A representative sample from each tumour was chosen and a 50 microm section was cut. The paraffin block of tumor was then divided into 4 equal parts and a 50 microm section was cut from each part. All tumour samples were analysed separately by flow cytometry. DNA ploidy heterogeneity was noted in 5/29 cases (17%). In three cases DNA-aneuploid stem cell lines were found only among the 4-part sections and were not detected when the whole tumor section was analysed.

DNA ploidy and S-phase in recurrent astrocytomas: a retrospective study by flow cytometry of deparaffinized specimens

Twenty-two patients with recurrent astrocytic tumors were treated surgically two or even three times. At the time of the first surgery 6 tumors were fibrillary astrocytomas (grade II), 9 anaplastic astrocytomas (grade III) and 7 glioblastomas (grade IV). Histopathological specimens from second surgery demonstrated in 12 cases signs of higher grades of malignancy. Flow cytometry (FCM) did not reveal any significant changes of S-phase fraction (p = 0.55). This study supports the theory that, given enough time, the histopathology of brain tumors change significantly from more benign forms to more malignant ones. The flow cytometry (FCM) could trace a weak tendency to higher S-phase fractions at the time of the second surgery. No apparent change of ploidy pattern was observed. In spite of the unequivocal histopathological changes of the recurrent astrocytomas the flow cytometry failed to indicate similar changes in terms of ploidy and S-phase fraction parameters.

Methodological aspects of flow cytometry DNA analysis in endometrial carcinoma, with special reference to sampling and reproducibility

Two adjacent paraffin-embedded sections manifested concordance in ploidy status in 96% of cases (45/47), and the standard deviation (SD) for SPF was 2.7%. Analysis of 'micro-heterogeneity', within a distance of < or = 700 microm, yielded results for concordant ploidy status in 94% of cases, and the SD for SPF was 1.9% (n = 17). Frozen and paraffin-embedded material yielded concordant results for ploidy status in 87% (39/45) of cases, and SPF values were significantly lower (mean difference 1.5%) in the frozen samples. Diagnostic and repeat curettage material yielded concordant results for DNA ploidy status in 85% (40/47) of cases, and no significant difference in mean SPF (12% vs. 11%) was found. Discordant DNA ploidy results were attributable to small differences in the DNA histograms influencing the interpretation of near-diploid, near-tetraploid and small non-diploid cell populations, and the influence of debris on SPF estimation. On the basis of our findings and the practical advantage we recommend paraffin-embedded material from diagnostic curettage for FCM DNA analysis; the results are available sooner and the handling and transportation of tumor samples is more convenient.

Comparison between flow cytometric and cytogenetic tumor cell DNA content using a simple flow sample preparation method: ploidy comparison of 86 fresh pediatric tumors

A comparison of tumor ploidy by flow cytometry (FL) and cytogenetics (CYG) was made in 86 fresh pediatric solid (n = 47) and hematopoietic (n = 39) tumors using simple sampling and semiautomated proprietary FL preparation methods and defined histogram interpretive criteria. Tumor karyotypes with 44-48 chromosomes were regarded as CYG diploid and other chromosomal complements CYG aneuploid for comparison purposes. Five histograms were uninterpretable and nine cases failed to produce 15 or more metaphases for karyotyping. Mean G0/G1 peak coefficients of variation of all 86 cases were 2.7 and 3.0 for the diploid and aneuploid populations, respectively. Of the 72 eligible cases, 41 were concordant diploid and 16 concordant aneuploid with an overall concordance of 79%. The DNA index and karyotypic index correlation coefficient was 0.92 for the 16 concordant aneuploid cases. Analysis of the 15 discordant cases highlights the limitations of both methods and of the histogram interpretive criteria and indicates that FL is probably more sensitive for detection of tumor aneuploidy as defined and detected by these methods.

DNA index and S-phase in primary brain tumors. A comparison between fresh and deparaffinized specimens studied by flow cytometry

Forty-nine primary intracranial tumors (33 astrocytomas, eight acoustic schwannomas, five oligodendrogliomas, and three miscellaneous tumors) were studied by flow cytometry. Each tumor specimen was divided into two portions: one was studied as an unfixed suspension stained with propidium iodide and the other after formalin fixation and paraffin embedding. The 50-microns sections from the paraffin blocks were deparaffinized, rehydrated, and enzymatically disintegrated, and the cells in suspension were stained with propidium iodide. Flow cytometry of the two portions showed a significant correlation between fresh and fixed specimens regarding the S-phase (r = 0.87) and a very close correlation fo the deoxyribonucleic acid (DNA) index (r = 0.95). When the 33 astrocytomas were analyzed separately, similar results were obtained (r = 0.86 for S-phase and r = 0.93 for DNA index, respectively). This study demonstrated a high correlation between fresh and fixed specimens for DNA ploidy and S-phase both in primary intracranial tumors in general and also in the selected subgroup of astrocytomas.

Soft tissue leiomyosarcoma. A population-based epidemiologic and prognostic study of 48 patients, including cellular DNA content

BACKGROUND

Leiomyosarcoma of soft tissue is a rare tumor. There are different opinions regarding epidemiology and prognosis.

METHODS

Epidemiology and prognosis were analyzed in a consecutive, population-based series of 48 patients with subcutaneous and deep-seated leiomyosarcoma in the extremities and trunk wall with a complete follow-up of a minimum of 3 years. Cutaneous tumors were not included.

RESULTS

The annual incidence was 0.13/10(5). The ratio of men to women was 1.2, and the median age was 65 years. The thigh was the most common location. Almost half of the tumors were subcutaneous. The median tumor size was 6 cm (range, 1-25 cm). All patients were treated with surgery, and in 19 cases it was combined with adjuvant radiation therapy or chemotherapy. The cumulative 5-year survival rate was 64%. Multivariate analysis indicated that age of 60 years or greater (relative risk [RR] = 8) and intratumoral vascular invasion (RR = 4) were independent risk factors for death resulting from tumor. DNA aneuploidy (RR = 4) and tumor necrosis (RR = 3) were associated with poor prognosis, but did not reach statistic significance.

CONCLUSIONS

Advanced age, vascular invasion, and DNA aneuploidy could be used to identify prognostic subgroups.

DNA ploidy analysis of effectiveness of radiation therapy for cervical carcinoma

Cellular DNA content from 30 patients with cervical carcinoma was determined using flow cytometry before and after radiation therapy (RT). The authors attempted to correlate changes in DNA content, tumor response to RT, and post-RT pathologic findings. Before RT, tumors from eight of 30 patients (26.7%) were diploid or near-diploid; tumors from 22 patients (73.3%) were aneuploid. After RT, diploid or near-diploid tumors were found in 23 patients (76.7%), and aneuploid tumors were observed in seven patients (23.3%). Aneuploidy disappeared in 15 of the patient tumors, and complete tumor response (CR) was observed in 13 of these 15 patients (86.7%). Pathologic examinations were negative in 12 of 15 cases and suspicious in one of 15 cases. Of the seven patients whose tumor aneuploidy did not change after RT, CR was observed in only two (28.7%). Pathologic examinations were positive in five of seven cases and suspicious in one of seven cases. The CR for the 22 patients with pre-RT aneuploid tumors was 15 of 22 (68.2%); the CR for the eight patients with pre-RT diploid tumors was two of eight (25%, P less than 0.01). From these data the authors conclude there is a direct correlation between DNA content and radiosensitivity in cervical carcinoma. Aneuploid tumors from these patients were more radiosensitive than diploid tumors, and they patients had a better clinical tumor response and improved pathologic findings.

Heterogeneity of squamous cell carcinomas of the oral cavity studied by flow cytometry

The DNA pattern was determined by flow cytometry in 76 samples from 16 squamous cell carcinomas of the oral cavity to assess intratumour DNA heterogeneity. Heterogeneous DNA content was found in 2 tumours (12%); both containing DNA diploid and DNA aneuploid cell clones. The remaining 14 tumours showed a homogeneous DNA distribution in the different specimens; 9 (56%) were diploid, 3 (19%) aneuploid and 2 (12%) were polyploid. The DNA non-diploid tumours were clinically more advanced than the DNA diploid ones (p less than 0.05). The tumour proliferation rate (fraction of cells in S-phase) was higher in aneuploid tumours than in diploid ones (p less than 0.01).

Influence of S-phase fraction on metastatic pattern and post-recurrence survival in a randomized mammography screening trial

Using static cytofluorometry, S-phase was determined on the primary tumors of 421 patients with breast carcinomas in stages I-III diagnosed 1981-85 during the second and third screening rounds of a randomized trial evaluating the effect of mammographic screening. Through December 1988, 82 patients had developed local and/or distant recurrence, 51 of whom had died of cancer during the same period. The distribution among sites of recurrence differed between patients with tumors detected by mammography screening and cancers diagnosed due to clinical symptoms. The mean S-phase fraction was highest in patients with liver or brain metastases and lowest in patients with metastases in subcutaneous and cutaneous tissue and lymph nodes only. In univariate analysis, survival after first recurrence was significantly associated with the site of primary recurrence, the disease-free interval, and node status and tumor size at diagnosis, as well as the S-phase level. The median survival period was 31.3. months for patients with a S-phase fraction below 6%, and 10.7 months in cases with S-phase exceeding 10%. Neither ploidy nor the estrogen receptor content had significant influence on post-recurrence survival. In Cox's multiple regression analysis, only metastatic site, disease-free interval, and S-phase fraction showed significantly independent prognostic value.

Flow cytometric measurements of DNA index and S-phase on paraffin-embedded early stage endometrial cancer: an important prognostic indicator

Paraffin-embedded curettage material from 120 patients with stage I and II endometrial cancer were analyzed by flow cytometry. The follow-up time in all cases was at least 5 years or until death. It was possible to determine DNA ploidy in 111 cases and S-phase was also evaluated in 92/111 cases. DNA ploidy and S-phase were then compared with the FIGO grading and clinical outcome. DNA ploidy results showed that 11% of grade 1 tumors were aneuploid, 14% of grade 2, 42% of grade 3, and 85% of the cases of uterine papillary serous carcinoma (UPSC) were aneuploid. Patients with tumors that showed an S-phase fraction below 5% had a cumulative 5-year cancer mortality of 7% whereas 49% of the patients with tumors having S-phase fraction above 10% died of their cancer. The prognostic significance of DNA and S-phase correlated fairly well with the FIGO grading as determined by a pathologist with special interest in gynecologic oncology and the DNA parameters added prognostic information independent of the FIGO grading.