Flow cytometric evaluation of ovarian cancer

Recent advancement of autophagy in polyploid giant cancer cells and its interconnection with senescence and stemness for therapeutic opportunities

Recurrent chemotherapy-induced senescence and resistance are attributed to the polyploidization of cancer cells that involve genomic instability and poor prognosis due to their unique form of cellular plasticity. Autophagy, a pre-dominant cell survival mechanism, is crucial during carcinogenesis and chemotherapeutic stress, favouring polyploidization. The selective autophagic degradation of essential proteins associated with cell cycle progression checkpoints deregulate mitosis fidelity and genomic integrity, imparting polyploidization of cancer cells. In connection with cytokinesis failure and endoreduplication, autophagy promotes the formation, maintenance, and generation of the progeny of polyploid giant cancer cells. The polyploid cancer cells embark on autophagy-guarded elevation in the expression of stem cell markers, along with triggered epithelial and mesenchymal transition and senescence. The senescent polyploid escapers represent a high autophagic index than the polyploid progeny, suggesting regaining autophagy induction and subsequent autophagic degradation, which is essential for escaping from senescence/polyploidy, leading to a higher proliferative phenotypic progeny. This review documents the various causes of polyploidy and its consequences in cancer with relevance to autophagy modulation and its targeting for therapeutic intervention as a novel therapeutic strategy for personalized and precision medicine.

The causes and consequences of polyploidy in normal development and cancer

Although nearly all mammalian species are diploid, whole-genome duplications occur in select mammalian tissues as part of normal development. Such programmed polyploidization involves changes in the regulatory pathways that normally maintain the diploid state of the mammalian genome. Unscheduled whole-genome duplications, which lead primarily to tetraploid cells, also take place in a substantial fraction of human tumors and have been proposed to constitute an important step in the development of cancer aneuploidy. The origins of these polyploidization events and their consequences for tumor progression are explored in this review.

Adjuvant chemotherapy for early-stage ovarian cancer: review of the literature

PURPOSE

This overview summarizes studies with acceptable quality and validity and presents a synthesis of the effectiveness on adjuvant therapy after surgery for early ovarian cancer (EOC) patients.

METHODS

The literature published between 1970 and 2006 was identified systematically by computer-based searches in MEDLINE and Cochrane library.

RESULTS

Twenty-two prospective randomized studies were analyzed, which included 4,626 patients. No difference between adjuvant chemotherapy (AC) and radiotherapy was found. There is agreement on that patients with stage IA, grade 1 tumors have excellent survival and do not need postsurgical therapy. The International Collaborative Ovarian Neoplasm 1/Adjuvant Chemotherapy in Ovarian Neoplasm trials were the first to show an effect on survival of AC, but in patients with adequate surgical staging, there was no additional effect of AC. For patients who are staged incompletely at the time of initial surgery, completion of the staging procedure with either laparoscopy or laparotomy is a reasonable approach before a final decision is made regarding the need for AC. If full staging cannot be performed due to medical contraindication or patient refusal, consideration of AC is reasonable in selected patients. Using prognostic variables such as grade, International Federation of Gynecology and Obstetrics substage, pretreatment of CA-125 < or = 30 U/mL, and DNA ploidy, it is possible to divide patients into risk groups to avoid overtreatment. Gynecologic Oncology Group study 157 suggests that it may be possible to minimize chemotherapy-induced toxicity by using three instead of six cycles of AC, although it is not known fully whether this will compromise effectiveness.

CONCLUSION

Future randomized studies in EOC will include the investigation of new targeted therapies and new prognostic factors in adequately staged patients.

Treatment of patients with early epithelial ovarian cancer

PURPOSE OF REVIEW

During 2003, the first randomized trials were published comparing adjuvant platin-based chemotherapy versus no treatment in early epithelial ovarian cancer.

RECENT FINDINGS

Recent findings of the European Organisation for Research and Treatment of Cancer Adjuvant ChemoTherapy In Ovarian Neoplasm and International Collaborative Ovarian Neoplasm-1 trials showed an improvement of overall survival of 8% in patients treated with adjuvant platin-based chemotherapy compared with observation. In a subgroup analysis, in 150 optimally surgically staged patients of the European Organisation for Research and Treatment of Cancer Adjuvant ChemoTherapy In Ovarian Neoplasm trial, there appears to be no benefit of adjuvant chemotherapy. In past years, it has been shown that degree of differentiation is a much stronger predictor of recurrence in early ovarian cancer than International Federation of Gynaecology and Obstetrics subclassification (Ia, Ib, Ic). It has also been shown that patients with bilateral tumors (Ib) have the same prognosis as International Federation of Gynaecology and Obstetrics stage Ic patients.

SUMMARY

During the past year, it has been shown that platin-based adjuvant chemotherapy improves recurrence-free and overall survival in early epithelial ovarian cancer. It should be emphasized, however, that this was demonstrated in patients in whom the true nature of early stage disease was doubtful in many patients due to incomplete surgical staging. In a subgroup of patients who are optimally surgically staged, adjuvant chemotherapy may be less effective. Theoretically, only a future trial randomizing optimal surgical staging versus adjuvant chemotherapy may be able to provide definitive conclusions, but such a trial would be almost impossible to conduct. In the meantime, optimal staging is advocated in all patients who are fit enough to undergo this procedure. Degree of differentiation should be incorporated in a new International Federation of Gynaecology and Obstetrics classification for stage I disease and in clinical decision making.

Does endometriosis really have premalignant potential? A clonal analysis of laser-microdissected tissue

Since 1925, epidemiological and histological evidence for an association between endometriosis and ovarian neoplasia has accumulated. Recently, publications assaying the clonality of a given cell population have implied endometriosis has premalignant properties. However, the human androgen receptor used as a marker in these studies is of highly questionable reliability due to the instability of its methylation pattern in nonmalignant cells and during the course of malignancy. Therefore, we decided to readdress the question of clonality of endometriotic foci by using an alternative assay based on a polymorphism of the phosphoglycerate kinase-1 gene. We overcame the limitation to using ovarian cysts (a problem encountered in other studies) by laser-microdissecting defined tissue fractions of interest. From the 13/29 informative patients, a total of 32 endometriotic samples from various sites was assayed. Only 2/32 samples from different patients bore monoclonal tissue. With one of those cases, we present the first direct evidence of the two morphological endometric compartments comprising a single biphasic developmental unit. Neither monoclonal patient was characterized by any outstanding clinical parameters, including neoplasia. Individual endometriotic foci from the only patient in this study with neoplasia was assayed as being polyclonal. Therefore, former studies stating endometriosis as premalignant have to be cautiously reinterpreted.

Systemic therapy for gynecological neoplasms: ovary, cervix and endometrium

Early-stage endometrial carcinomas should be treated by total abdominal hysterectomy and bilateral salpingo-oophorectomy. In a small subset of patients, who wish to have children, conservative treatment (hormonal therapy) could be considered. The most effective agents for palliation of advanced disease are doxorubicin plus cisplatin.

20q13 and cyclin D1 in ovarian carcinomas. Analysis by fluorescence in situ hybridization

In ovarian carcinomas, alterations of the chromosomal region 20q13 and the cyclin D1 gene have been described. This study has sought to determine their prognostic significance. Fluorescence in situ hybridization (FISH) on dissociated nuclei and paraffin sections with DNA probes for 20q13.2 and cyclin D1, as well as immunohistochemistry (cyclin D1), were applied to formalin-fixed tissue of 69 invasive ovarian carcinomas, mainly of serous type. On dissociated nuclei 33/47 cases (70%) and on tissue sections 13/66 cases (20%) demonstrated an increase of 20q13.2 copies. The presence of > or =4 copies per nucleus (isolated nuclei) and > or =3 copies per nucleus (sections) was associated with an adverse prognosis (Kaplan-Meier for FIGO stage III after stratification for residual tumour: p=0.0049 and p=0.03, respectively). Thirty-four out of 47 cases (72%) showed an increase of cyclin D1 copies. Kaplan-Meier analysis for FIGO stage III after stratification for residual tumour>2 cm or < or =2 cm revealed an unfavourable outcome for cases with more than two cyclin D1 copies (p=0.04). No correlation was seen between FISH and immunohistochemistry. Multivariate analysis identified residual tumour (p=0.0002), 20q13.2 gain (p=0.0004) and cyclin D1 gain (p=0.0343) as independent prognostic factors. It is concluded that gains of chromosomal region 20q13.2 and the cyclin D1 gene are frequent and biologically important events, with prognostic relevance, in advanced ovarian carcinomas.

Molecular aspects of ovarian cancer. Is gene therapy the solution?

Genetic abnormalities of cancer cells are complex and usually nonspecific. Genetic anomalies specific to ovarian cancer have not been reported. This article focuses on what molecular anomalies are known in ovarian cancer and describes the first trials that have used transfer of genes to reestablish a normal cellular function in this disease. Suicide gene therapy has been the prototype of this new therapeutic approach.

Circadian rhythm of cell division

The existence of circadian oscillations in the level of hormones, in numerous physiological parameters, in toxicity and in behavior is now fully recognized in all living organisms. In contrast, the synchronisation and regulation of cell proliferation by circadian rhythms in vivo is only starting to be appreciated. This article reviews the experimental evidence for circadian synchronisation of cell division in different mammalian tissues (mainly the gastro-intestinal tract and hemapoietic system), including tumoral tissues. The possible causes of this coupling of the cell cycle phases to the circadian rhythm are discussed. Testing of novel antitumour agents using murine models should take into consideration the temporal difference between murine and human circadian control of proliferation (the peak of DNA synthesis occurs during the activity period, i.e. during daytime in man, and at night-time in mice and rats). Experimental and clinical data clearly support the important implications of the circadian control of the cell cycle in the optimisation of cancer chemotherapy, both for reducing toxicity and increasing the antitumour effects.

The genetics of ovarian cancer: molecular biology and clinical application

Ovarian cancer is the fifth most common malignancy among American women and the fourth leading cause of cancer death. The rapid advances in molecular genetic analysis, presymptomatic detection, and treatment of ovarian cancer are staggering. In this review, both the genetic component and the molecular biology of ovarian cancer are discussed, as well as current recommendations for genetic counseling. It is important for the practicing obstetrician and gynecologist to become familiar with these concepts, for it is he or she who will likely serve as a primary resource of information for these patients.

DNA ploidy and MYC DNA amplification in ovarian carcinomas. Correlation with p53 and bcl-2 expression, proliferative activity and prognosis

There is increasing evidence that DNA ploidy is a prognostic factor in ovarian carcinomas, but it is uncertain whether MYC DNA amplification is an epiphenomenon of DNA nondiploidy or a distinct biological change with an impact on the clinical course of the disease. To clarify these issues we analysed DNA ploidy by flow and image cytometry and MYC copy number by polymerase chain reaction in archival material from ovarian carcinomas with known follow up. The results were compared with proliferative activity (Ki67 index) and p53 and bcl-2 expression. DNA cytometry revealed nondiploidy in 84 of 144 cases (58.3%). Nondiploidy was statistically significantly correlated with histological tumour type, histological grade, Ki67 index > 10%, FIGO stage, presence of residual tumour after debulking surgery and adverse postoperative outcome. Furthermore, DNA nondiploidy was associated with p53 accumulation. We found that 84.9% of the p53-positive cases were nondiploid. This points to the paramount importance of wild type p53 for the maintenance of genome integrity in this tumour type. MYC DNA amplification was seen in 33.8% (26/77 cases) of ovarian carcinoma. There was no correlation between MYC DNA amplification and histological tumour type, histological grade, FIGO stage, DNA ploidy, proliferative activity or prognosis. However, when p53 and bcl-2 expression was taken into account, a statistically significant correlation between gene alteration or expression patterns and histological tumour type was revealed. The group of mucinous carcinomas demonstrated both MYC DNA amplification and strong bcl-2 expression in 50% and contained the largest fraction of cases without aberration (37.5%). Endometrioid carcinomas were characterized by strong bcl-2 expression in 85%, whereas serous and undifferentiated carcinomas predominantly exhibited p53 alterations, frequently accompanied by bcl-2 overexpression or MYC DNA amplification. Thus, in interaction with other genes MYC DNA amplification may play a role in the determination of the varying differentiation patterns of ovarian carcinomas.

Ifosfamide and cisplatin as neoadjuvant chemotherapy for advanced cervical carcinoma

A phase II trial was performed to evaluate the efficacy and toxicity of a combination of cisplatin (CDDP) and ifosfamide (IFX) as neoadjuvant chemotherapy in advanced cervical carcinoma (ACC). Between August 1991 and September 1993, 57 untreated patients with stages IIB to IVA were entered into this study. Median age was 44 years (range, 25 to 74 years). The distribution by stages (International Federation of Gynecology and Obstetrics) was as follows: IIB, 31 patients; IIIB, 21 patients; and IVA, 5 patients. Therapy consisted of IFX 2000 mg/m(2) 1-h i.v. infusion days 1 to 3; mesna 400 mg/m(2) i.v. bolus at hours 0 and 4, and 800 mg p.o. at hour 8; and CDDP 100 mg/m(2) on day 3. Cycles were repeated every 28 days for a total of three courses. Both staging and response assessment were performed by a multidisciplinary team. An objective response was observed in 30 of 56 patients (54%; 95% confidence interval, 41 to 67%). Four patients (7%) had a complete response (CR) and 26(46%) had a partial response (PR). Patients with CR or operable PR underwent surgery, otherwise received definitive radiotherapy. Toxicity was mild to moderate. There were no toxicity related deaths. These results indicate that IFX/CDDP is an active combination for ACC with mild toxicity. The results of phase III studies that evaluate the real impact of neoadjuvant chemotherapy are awaited.

Fluorescence drift detection as a novel QC procedure for DNA cell-cycle analysis

The goal of this work was to develop an objective, quantitative, and reproducible method of detecting fluorescence drift which may have occurred during DNA cell-cycle data acquisition. Quality control software, "TruPloid," is described that analyzes list-mode files to detect and quantify fluorescence drift using three separate statistical tests. We show that fluorescence drift may lead to a variety of measurement artifacts including high coefficients of variation, obscuring of small populations and creation of distinct artificial peaks. Forty percent of 50 archived list-mode files displayed fluorescence drift, which demonstrates the need for detection methods to deal with this source of DNA cell-cycle histogram artifacts.

Cellular DNA content and survival in advanced ovarian carcinoma

BACKGROUND

The prognosis of patients with advanced ovarian cancer is generally poor. To date, no satisfactory methods for predicting individual prognosis have been reported, especially in patients with little or no residual tumor after debulking.

METHODS

The authors investigated in a retrospective study the prognostic significance of nuclear DNA content as measured by flow cytometry of the tumor specimens from 184 women with nonpretreated International Federation of Gynecology and Obstetrics Stage III and IV ovarian cancer. Clearly defined inclusion criteria for the study population were used.

RESULTS

Seventy-one (39%) cancers were diploid, whereas 113 (61%) were aneuploid. Ploidy showed a significant correlation with clinical and morphologic features such as age, histologic grade, serous histologic type, and residual tumor after debulking. No significant correlation was found between ploidy and ascites, estrogen- and progesterone receptor levels, and elevated pretreatment CA-125 levels. Univariate analysis showed significant correlations between overall survival and histologic grade (P = 0.003), patient age (P = 0.001), residual tumor after primary surgery (P < 0.001), stage (P = 0.019) and ploidy (P = 0.009). Multivariate analysis revealed residual tumor (P < 0.001) and age (P = 0.051) to be associated independently with survival. Ploidy was not established as an independent prognostic factor.

CONCLUSIONS

These results suggest that abnormalities of the nuclear DNA content in advanced ovarian carcinomas are associated with various clinical and morphologic prognosticators, but that ploidy is not an independent prognostic factor for survival.

Intratumoral DNA heterogeneity correlated with lymph node involvement and surgical staging in epithelial ovarian cancer by flow cytometry

BACKGROUND

Flow cytometry (FCM)-measured DNA content may be a predictor in the prognosis of ovarian cancer. Multiple specimens taken from the same ovarian tumor may show a variation in DNA content (i.e., intratumoral DNA heterogeneity). We measured the FCM DNA content of multiple specimens from the same tumor in ovarian cancer, and the relationship among DNA ploidy, intratumoral DNA heterogeneity, retroperitoneal lymph node involvement, and surgical staging was evaluated.

METHODS

Forty-one patients with primary epithelial ovarian cancer were included in the study. The FCM-measured DNA content of multiple fresh tumor specimens taken from different parts of the same ovarian tumor from each patient was measured. When aneuploidy was observed in at least one specimen from the same tumor, the tumor was defined as an aneuploid tumor. If there were two or more different aneuploid stem lines with a variation of DNA indices (differences of the DNA indices > 0.15) from the same tumor, the presence of intratumoral DNA heterogeneity was defined.

RESULTS

Diploid tumor was found in 8 (19.5%) of the 41 patients, and aneuploid tumor with intratumoral DNA heterogeneity was found in 20 (48.8%). None of the eight patients with diploid tumors demonstrated lymph node involvement. In contrast, lymph node involvement was found in 14 (70.0%) of 20 patients with intratumoral DNA heterogeneity. There was a significant different incidence of lymph node involvement between the groups with and without intratumoral DNA heterogeneity (P < 0.01). The incidence of intratumoral DNA heterogeneity significantly correlated with the International Federation of Gynecology and Obstetrics staging (P < 0.01), while that of aneuploid tumor did not.

CONCLUSIONS

Intratumoral DNA heterogeneity reflected a malignant potential for lymph node involvement and its progression in epithelial ovarian cancer.

Neoadjuvant therapy in cancer treatment

Neoadjuvant therapy has come to play an increasingly prominent role in the treatment of cancer. Originally defined as systemic therapy given before local treatment, the concept has been extended to include radiation therapy given before surgery. Potential advantages include improved local and distant control, direct evaluation, and organ-sparing treatment. Potential disadvantages include increased toxicity and cost, potential delay in effective treatment, and obscuring of pathologic staging. Neoadjuvant therapy in cancer treatment may be viewed in three categories: tumors in which neoadjuvant treatment has been shown effective, thus becoming standard therapy; tumors in which it has been shown to facilitate organ-sparing, and tumors in which its utility has not been shown. For patients with osteogenic sarcoma, for example, preoperative chemotherapy and limb salvage therapy have become the standard of care. Response to chemotherapy, ascertained by histologic review of the surgical specimen, can be used to tailor postoperative chemotherapy. In patients with advanced laryngeal squamous cell carcinoma, neoadjuvant chemotherapy followed by radiation has permitted laryngeal preservation in a majority of patients without compromising overall survival. Phase II and III studies conducted in women with breast cancer have demonstrated promising results for neoadjuvant chemotherapy given before radiation therapy and/or surgery. Phase III studies to compare neoadjuvant therapy to standard therapy in patients with breast cancer are underway. For neoadjuvant therapy, as with other innovations in cancer treatment, it is crucial that a new strategy must be compared closely to standard therapy in terms of recurrence, survival, and impact on organ sparing, as well as quality of life and treatment costs.