Cyclin E and p53: The Dynamic Duo in Ovarian Tumor Pathogenesis

doi:10.21203/rs.3.rs-4130179/v1

Objectives: The aim of this study is to report on the expression of p53 and cyclin E in ovarian tumors and to analyze their correlations with the clinicopathological parameters. Another aim is to examine if aberrant expression of both cyclin E and p53 might increase the malignant potential of ovarian tumors.

Methods: Seventy-two paraffin-embedded ovarian tumor tissues were immuno-histochemically investigated for expression of p53, and cyclin E. The tumor tissues were benign (15), borderline (12), and malignant ovarian tumors (45). The expression of these two markers was analyzed with the correlations with the clinicopathological parameters in a subgroup of 34 epithelial ovarian cancers.

Results: p53 and cyclin E expression was markedly increased in malignant ovarian tumors as compared to benign tumors p-value= (0.002, 0.014) respectively. Expression of p53 in epithelial ovarian cancer tissues was significantly correlated with the stage of the tumor (p=0.015), whereas cyclin E expression was significantly associated with the histomorphologic tumor type (p= 0.001). There was significant correlation between p53 and cyclin E expression in the 72 ovarian tumor tissues p= 0.019.

Conclusions: There was a positive association between the expression of p53 and cyclin E and malignant progression of ovarian tumors. In epithelial ovarian cancers, p53 and cyclin E expressions were significantly correlated with the stage and histomorphologic tumor type, respectively.

Cyclin E

ovarian tumors

ovarian cancer

immunohistochemistry

molecular genetics

prognosis

prognostic marker

p53

Ovarian tumors are classified into three main types: epithelial tumors, germ cell tumors, and sex cord /stromal tumors. Epithelial tumors are the most common (account for approximately 60% of all ovarian neoplasms and 80-90% of malignant ovarian tumors) and occur primarily in adults. Epithelial tumors are further subdivided into three distinct biological categories: benign, borderline, and invasive carcinoma. Surface epithelial neoplasms are also classified into histological subtypes based on the type of epithelial differentiation that is present in the tumor. The subtypes include serous, mucinous, endometrioid, clear cell, and transitional cell. Serous tumors are the most common subtype[1]. Ovarian cancer is the most lethal gynecological malignancy [2]. In the Western world, it is considered the seventh most common type of cancer among females, after breast, bowel, and lung malignancy [3] and the second most common gynecologic malignancy after endometrial carcinoma in the USA, where it carries a higher mortality rate than all other female genital tract cancers combined [3]. The risk of developing ovarian cancer is estimated to be one case in 75 women [4]. The incidence increases with age, reaching its peak in the eighth decade [5]. The age-standardized incidence rate of ovarian cancer in Jordan is 4.6 cases per 100,000 females [6]. Ovarian cancer has a high frequency of metastasis [7]. Because there are no specific early symptoms, most of the patients are diagnosed at an advanced stage, whereby therapy is ineffective [8].

Ovarian cancer usually carries poor prognosis, and despite the recent advances in surgery and chemotherapy, these cancers continue to be fatal in far too many cases. The overall survival for patients with advanced disease is only 15-25% at 5 years [9].

Cell cycle progression is regulated by proteins called cyclin dependent kinases (CDKs) that are activated by binding to subunits known as cyclins [10]. Cyclin E is a 395-amino acid protein derived from a gene located on chromosome 19, and it is one of the most important cell cycle regulators that play an important role in normal cell proliferation and development through promotion of the S phase [11]. Cyclin E associates with cdk2 and activates its serine-threonine kinase activity shortly before entry into S phase [12]. Once cells enter S phase, the timely inactivation of cyclin E and E2F activities are thought to be equally important for cell cycle progression. The activity of cyclin E-cdk2 complex peaks at the G1-S transition, after which rapid degradation of cyclin E is mediated by ubiquitin-dependent proteolysis, and its phosphorylation by its own catalytic partner, cdk2, signals its destruction and replacement by cyclin A [13]. Elevated cyclin E protein levels have been associated with a variety of human malignancies [14]. Overexpression of cyclin E decreases cell size, diminishes the requirement for growth factors, and accelerates the G1 phase of the cell cycle [15]. Cyclin E is one of the most important cell-cycle regulators, and when deregulated it causes deregulation of the cell cycle which may result in oncogenesis [16].

P53 is a tumor suppressor gene which acts as a negative regulator of cell growth and required for the transcription of a number of genes involved in cell-cycle control and DNA synthesis [17]. P53 inhibits proliferation by binding to transcriptional regulatory elements in DNA, and is thought to play an active role in preventing cancer [18]. P53 functions as a surveillance mechanism in which cells that undergo genetic damage are arrested in G1 phase to allow for DNA repair, or apoptosis [19]. If the function of p53 is lost from any cell then the ability to eliminate potentially cancerous cells is lost and cancer can form [20]. Expression of abnormal p53 has been detected in more than half of the epithelial ovarian cancers [21].

The aims of this study are to determine the significance of p53, and cyclin E expression in patients with ovarian tumors, and to evaluate correlations and levels of expression of p53, and cyclin E with the classical clinicopathological prognostic factors in epithelial ovarian cancers such as patient age, tumor stage, differentiation grade and histomorphologic tumor type. Another aim is to determine the value of the combination of cyclin E and p53 expression in patients with ovarian tumors (benign, borderline, and malignant).

Tissue samples collection:

Ovarian tumor tissues of 72 Jordanian patients operated upon during the period (1994-2004) were obtained from the Pathology Department at King Abdullah University Hospital. These tumors were classified as 45 malignant, 12 borderline and 15 benign. The malignant cases were 34 epithelial,11 germ cell/sex cord ovarian cancer tissues.

Clinicopathological parameters of the 34 patients with epithelial ovarian cancer are summarized as follows. The median age was 50 years (range 20-84). The stage of the cancer was determined according to the International Federation of Gynecology and Obstetrics (FIGO) classification [22] . Eighteen patients were in early stages (I/II), and 16 were in advanced stages (III/IV). Tumors were graded and classified by a gynecological pathologist according to WHO criteria [23] ; whereby 5 cases were well differentiated (grade-I), 12 moderately differentiated (grade-II), and 17 poorly differentiated (grade-III). The histomorphologic tumor type included 20 serous adenocarcinoma, and 14 mucinous/others carcinoma. All slides were reviewed by experienced pathologist to reconfirm the diagnosis and to select the representative blocks to be used for the detection of the markers concerned.

Immunohistochemical staining:

Formalin-fixed paraffin-embedded tissuesections (3 µm thick) were cut and mountedon Vectabond-coated slides (Vector Laboratories). Sections were dewaxed in xylene and rehydratedthrough graded alcohols to fresh distilled water. Antigen retrieval was accomplished by heating in 10X reveal solution in Decloaking chamber (Biocare Medical CA, USA) for 4 min, and then immersed in 10X PBS for 15 min. The sections were incubated at room temperature for one hour with mouse monoclonal anti-p53 (1:500), and rabbit polyclonal anti-cyclin E antibody (1:200) (Santa Cruz Biotechnology, Inc. Germany), then washed. The immunostaining was performed by labeled streptavidibiotin (LSAB) method, and immunoreactivity was revealed by 3,3-diaminobenzidin (DAB) as a chromogen (Biocare Medical CA, USA). All sections were counterstained with hematoxylin and examined by light microscopy. Each experiment was independently performed twice. Throughout the study, sections from breast cancer tissues known to express cyclin E and p53 proteins were analyzed in parallel to serve as positive controls. Omission of the primary antibody from these samples acted as a negative control.

Immunostaining assessment and evaluation:

The immunohistochemistry (IHC) results were evaluated by an experienced pathologist. Scoring of p53 and cyclin E expression was performed as described in previously published scoring system, whereby intensity and percentage of positive staining whether nuclear or nuclear and cytoplasmic was taken in consideration [24] .

Each tumor was scored according the intensity of staining of the nucleus and cytoplasm as follows: no staining = 0; low level = 1; medium staining = 2; and strong staining = 3. The percentage of stained cells as follows: 0% = 0; < 10% = 1; 10-50% = 2; 51-80% = 3; and >80% = 4 [24] .

These percentages were calculated using at least three fields of 40x. The final score was calculated by multiplying the intensity by the percentage. Using this calculation, the score value was ranging from zero to 12.

Any cytoplasmic staining without nuclear staining was judged as negative [25] . For statistical analysis, scores of (1-7) for p53 were considered weak, and (8-12) were considered strong. Cyclin E staining results were considered weak from (1-5), and strong from (6-9). Scoring of all sections was performed without prior knowledge of the clinicopathological information.

Statistical Analysis:

Chi-square test was performed to determine the association between malignant progression and each of the proteins p53 and cyclin E expression, as well as, to examine the association between the expression of these proteins and the clinicopathological parameters in epithelial ovarian cancers. Statistical analysis was performed using the Statistical Package for the Social Sciences Software Program version 26 (SPSS^®, Inc., Chicago, Illinois, USA). Differences were considered statistically significant at p<0.05.

Correlation of p53, and cyclin E expression with malignant progression:

Expression of p53 and its association with malignant progression are shown in Table 1. P53 expression (weak or strong) was observed in 63.89% of all ovarian tumor cases, and was markedly increased in malignant ovarian tumors (68.89%) as compared to benign cases (40%). On the other hand, the expression of p53 in the borderline cases was observed in 75% of the cases with weak level of staining.

Staining of cyclin E was observed mainly in the nucleus or nucleus and cytoplasm. Expression of cyclin E and its association with malignant progression are shown in Table 2. Cyclin E expression was observed in 70.83% of all ovarian tumor cases. It was markedly increased in malignant ovarian tumors (75.55%) as compared to benign (40%). On the other hand, the expression of cyclin E in borderline ovarian tumors was observed in 91.67% of the cases consisting of weak expression (50%) and strong expression (41.67%). P53 and cyclin E expression in ovarian tumor tissues were associated directly with malignant progression (p= 0.002, and 0.014, respectively).

Correlation of p53, and cyclin E expression in epithelial ovarian cancer with the clinicopathological parameters:

Expression of p53 and cyclin E corresponding to each of the four clinicopathological parameters studied (age, stage, grade, and histomorphologic tumor subtype) are presented in Table 3 and 4, which clearly shows that expression of p53 was associated with the stage of the tumor (p=0.015), and that cyclin E expression was significantly associated with the histomorphologic tumor type of ovarian cancer tissues (p=0.001). Expression of cyclin E was seen in 90% of the serous adenocarcinoma compared with 64.29% in the mucinous/others tumor subtypes.

Co-expression of p53 and cyclin E:

There was correlation between p53 and cyclin E expression on the whole sample (72 patients). Pearson chi-square was significant with p-value = 0.019.

The 72 cases of ovarian tumor results showed relationships among expressions of p53 and cyclin E (Table 5), which clearly showed that p53 positive staining was found in 63.89% (weak 41.67%, strong 22.22%), and cyclin E positive staining was found in 70.83% (weak 44.44%, strong 26,39%). The co-expression of p53 and cyclin E was found in 37 (51.39.%) cases.

In ovarian cancer the clinical decision-making is currently based on so-called conventional clinical and histopathologic prognostic factors such as patient age, tumor stage, differentiation grade and histological tumor type. However, the clinicopathologic criteria currently used to predict survival are largely inadequate [26]. The search for new tumor markers and understanding the timing and the degree of the molecular marker expression in the malignant progression of these cancers is especially important in relation to evaluating the use of these markers to improve management, and contribute to early diagnosis of ovarian cancer. In addition, some of these markers can be used as a prognostic indicator, and therefore guiding therapeutic choices.

Inactivation of the tumor suppressor gene and deregulation of cyclin E are frequent in human ovarian cancer. P53 is a 53 kilodalton nuclear phosphoprotein with tumor suppressor activity. It acts as a transcription factor, having the ability to transactivate some genes, and suppress the transcription of others [18]. The p53 tumor suppressor gene plays a major role in cell cycle control and growth arrest following DNA damage [27]. In normal cells, p53 presence is below IHC detection limit [28].Abnormal p53 protein is resistant to degradation and has a prolonged half-life which allows its detection by IHC staining [29].

Mutations in p53 are the most common genetic alterations in human malignancies. One of the most studied prognostic markers in ovarian cancer so far is the tumor suppressor gene p53. P53 is frequently mutated in ovarian cancer, and the expression of its protein product has been linked to poor clinical outcome in ovarian carcinoma [30].

In this study, p53 and cyclin E expression in ovarian tumor tissues were associated directly with malignant progression p= 0.002, and 0.014, respectively, which is consistent with other studies [31]. Sui et al found that the expression of cyclin E and cdk2 in ovarian tumor tissues were gradually increased from benign to borderline to malignant tumors [31].

When we investigated the correlations of p53 and cyclin E expression in the 31 epithelial ovarian cancer tissues with clinicopathological parameters (tumor subtype, age, stage, grade of the tumor), it was found that p53 expression was associated with tumor stage (p=0.015). P53 expression was found in 66.67% of early stages (I/II) and increased to 93.75% in advanced stages (III/IV). These results are consistent with other previous studies [32-34].

Our study showed that cyclin E expression in 51 (70.83%) of 72 ovarian tumor tissues, and high expression was found in 12 (35.29%) of epithelial ovarian cancers which is consistent with previous studies. Muller et al reported cyclin E expression in 13.6% of 413 cases studied [35]. Kim et al observed 100% cyclin E expression in their 30 cases [36]. These differences in the results may be due to methodological variability among the different studies, different patient populations, sample number, and different antibodies used for the detection of target proteins.

Furthermore, our results indicate a significant correlation between cyclin E expression and the histomorphologic tumor subtype (serous carcinoma versus mucinous/other tumor types) (p=0.001), where high expression of cyclin E directly proportion to the cell type (serous carcinoma). This result is consistent with the results of Schraml et al who found overexpression of cyclin E was more in serous compared with other tumor subtypes [37].

While Rosenberg et al found a significant difference in the frequency of the cyclin E staining pattern between non-serous and serous ovarian tumor subtypes (p=0.0002), where they reported that 85% of the cases were cyclin E-positive in non-serous tumors, compared to 29% of serous ovarian tumors [38].

Cyclin E is an independent prognostic factor in patients with ovarian carcinoma. Milde-Langosch et al reported that there were trends pointing to an association of higher age and positive cyclin E immunoreactivity with an unfavorable prognosis in ovarian cancers [24]. Rosen et al reported that overexpression of cyclin E was significantly associated with clear cell, poorly differentiated, and serous carcinoma, high-grade tumors, late-stage disease, age older than 60 years at the time of diagnosis, suboptimal cytoreduction, and poor outcome. These authors suggested that the accumulation of cyclin E protein may be a late event in tumorigenesis and may contribute to disease progression in patients with ovarian cancer [39].

In this study, no association was found between p53 and cyclin E expression. Sui et al reported that patients with cyclin E overexpression had a low overall survival rate. The combined phenotype of p27 (-)/cyclin E (++)/cdk2 (++) was independently related to poor prognosis. These authors suggested that the loss of p27 expression and overexpression of cyclin E or cdk2 were significantly associated with malignancy in ovarian tumors. p27 and cyclin E proteins may be valuable prognostic factors for epithelial ovarian carcinoma patients. Furthermore, the combined evaluation of p27/cyclin E/cdk2 may provide the most important prognostic implication [31]. Sawasaki et al reported that the cyclin E expression was found in 13 of 30 (43%) ovarian cancers, while p53 protein accumulation was detected in 12 of 30 (40%) ovarian cancers examined. There was a significant inverse correlation between cyclin E mRNA overexpression and p53 protein accumulation. These authors suggested that cyclin E overexpression frequently occurs in ovarian cancers without p53 protein accumulation and that cyclin E might have an important effect on the development of a limited number of ovarian cancers [40]. Rosenberg et al Cyclin E expression, in contrast to cyclin D1 expression, is marginally associated with short-term survival in univariate analysis for a group of 53 women. Among the short-term survivors, 15 (65%) of 23 were positive for cyclin E expression, compared with only 11 (37%) of 30 long-term survivors (P = 0.054). This association remained significant (P =.04) in a logistic regression analysis adjusted simultaneously for performance status and extent of residual disease, the 2 strongest predictors of survival in our study.

We also found a significant difference in the frequency of the cyclin E staining pattern between nonserous and serous ovarian tumor subtypes (P =.0002). Immunostaining for levels of cyclin E and p27(KIP1) expression may have potential as prognostic markers in the management of ovarian cancer [38]. This discrepancy among different studies may be attributable to differences in the number of the tumor subtypes (serous, nonserous), sample size and the population which investigated. Further studies are needed to determine whether such correlations reflect the complex role of these factors which may be played in the cell cycle regulation [41].

In conclusion, expression of p53 and cyclin E were significantly associated with malignant progression in ovarian tumors. P53 and cyclin E were associated with stage and the histomorphologic tumor subtype of epithelial ovarian cancer tissues, respectively.

CDKs, cyclin-dependent kinases; CDKIs, cyclin-dependent kinase inhibitors; IHC, immunohistochemistry

Author Contributions

Conceptualization, A.Z and K.B; methodology, A.Z and K.B.; data curation, A.Z, A.A, M.A, L.A.; writing—original draft preparation, A.Z, A.A, M.A, L.A writing—review and editing, A.Z, A.A, M.A, L.A.; supervision, K.B; funding acquisition, Jordan University of Science and Technology. All authors have read and agreed to the published version of the manuscript.

Funding: This study was made possible with funding from Jordan University of Science and Technology, showing their support for academic research.

Institutional Review Board Statement: This research study received approval from the Institutional Review Board of Jordan University of Science and Technology, ensuring that it adheres to ethical guidelines and standards for human research.

Informed Consent Statement: All participants provided informed consent prior to their involvement in this research study.

Data availability statement: The data supporting this study's findings are available from the corresponding author upon reasonable request.

Conflict of interest: The authors declare no conflict of interest.

Hanby, A.M. and C. Walker, Tavassoli FA, Devilee P: Pathology and Genetics: Tumours of the Breast and Female Genital Organs. WHO Classification of Tumours series-volume IV. Lyon, France: IARC Press: 2003. 250pp. ISBN 92 832 2412 4. Breast Cancer Research, 2004. 6: p. 1-2.
Momenimovahed, Z., A. Tiznobaik, S. Taheri, and H. Salehiniya, Ovarian cancer in the world: epidemiology and risk factors. International journal of women's health, 2019: p. 287-299.
Ferlay, J., M. Colombet, I. Soerjomataram, D.M. Parkin, M. Piñeros, A. Znaor, et al., Cancer statistics for the year 2020: An overview. International journal of cancer, 2021. 149(4): p. 778-789.
Reid, B.M., J.B. Permuth, and T.A. Sellers, Epidemiology of ovarian cancer: a review. Cancer biology & medicine, 2017. 14(1): p. 9.
Ali, A.T., O. Al-ani, and F. Al-ani, Epidemiology and risk factors for ovarian cancer. Menopause Review/Przegląd Menopauzalny. 22(1).
Al-Kayed, S. and B. Hijawi, Cancer incidence in Jordan 1998 report. The Hashemite Kingdom of Jordan. Amman (HKJ): Ministry of Health, 2000.
Zhang, J.-J., D.-Y. Cao, J.-X. Yang, and K. Shen, Ovarian metastasis from nongynecologic primary sites: a retrospective analysis of 177 cases and 13-year experience. Journal of Ovarian Research, 2020. 13(1): p. 1-10.
Henderson, J.T., E.M. Webber, and G.F. Sawaya, Screening for ovarian cancer: updated evidence report and systematic review for the US preventive services task force. Jama, 2018. 319(6): p. 595-606.
Yang, S.-P., H.-L. Su, X.-B. Chen, L. Hua, J.-X. Chen, M. Hu, et al., Long-term survival among histological subtypes in advanced epithelial ovarian cancer: population-based study using the surveillance, epidemiology, and end results database. JMIR Public Health and Surveillance, 2021. 7(11): p. e25976.
Graña, X. and E.P. Reddy, Cell cycle control in mammalian cells: role of cyclins, cyclin dependent kinases (CDKs), growth suppressor genes and cyclin-dependent kinase inhibitors (CKIs). Oncogene, 1995. 11(2): p. 211-220.
Fagundes, R. and L.K. Teixeira, Cyclin E/CDK2: DNA replication, replication stress and genomic instability. Frontiers in cell and developmental biology, 2021. 9: p. 774845.
Malumbres, M., Cyclin-dependent kinases. Genome biology, 2014. 15(6): p. 1-10.
Hume, S., G.L. Dianov, and K. Ramadan, A unified model for the G1/S cell cycle transition. Nucleic acids research, 2020. 48(22): p. 12483-12501.
Guerrero Llobet, S., B. van der Vegt, E. Jongeneel, R.D. Bense, M.C. Zwager, C.P. Schröder, et al., Cyclin E expression is associated with high levels of replication stress in triple-negative breast cancer. NPJ breast cancer, 2020. 6(1): p. 40.
Chu, C., Y. Geng, Y. Zhou, and P. Sicinski, Cyclin E in normal physiology and disease states. Trends in cell biology, 2021. 31(9): p. 732-746.
Kok, Y.P., S. Guerrero Llobet, P.M. Schoonen, M. Everts, A. Bhattacharya, R.S. Fehrmann, et al., Overexpression of Cyclin E1 or Cdc25A leads to replication stress, mitotic aberrancies, and increased sensitivity to replication checkpoint inhibitors. Oncogenesis, 2020. 9(10): p. 88.
Williams, A.B. and B. Schumacher, p53 in the DNA-damage-repair process. Cold Spring Harbor perspectives in medicine, 2016. 6(5).
Sullivan, K.D., M.D. Galbraith, Z. Andrysik, and J.M. Espinosa, Mechanisms of transcriptional regulation by p53. Cell Death & Differentiation, 2018. 25(1): p. 133-143.
Chen, J., The cell-cycle arrest and apoptotic functions of p53 in tumor initiation and progression. Cold Spring Harbor perspectives in medicine, 2016. 6(3): p. a026104.
Zhang, C., J. Liu, D. Xu, T. Zhang, W. Hu, and Z. Feng, Gain-of-function mutant p53 in cancer progression and therapy. Journal of molecular cell biology, 2020. 12(9): p. 674-687.
Ronchi, S., S. Facchi, E. Di Lauro, L. Libera, I.W. Carnevali, F. Zefiro, et al., Immunohistochemical and molecular pattern of p53 in epithelial ovarian cancers negative for germline BRCA1/2 variants. Pathology-Research and Practice, 2024: p. 155183.
Pecorelli, S., J. Benedet, W. Creasman, J. Shepherd, and F.C.o.G. Oncology, FIGO staging of gynecologic cancer. International Journal of Gynecology & Obstetrics, 1999. 65(3): p. 243-249.
Scully, R.E., T. Bonfiglio, R. Kurman, S.G. Silverberg, and E. Wilkinson, Histological typing of female genital tract tumours. 2012: Springer Science & Business Media.
Milde-Langosch, K., M. Hagen, A.-M. Bamberger, and T. Löning, Expression and prognostic value of the cell-cycle regulatory proteins, Rb, p16MTS1, p21WAF1, p27KIP1, cyclin E, and cyclin D2, in ovarian cancer. International journal of gynecological pathology, 2003. 22(2): p. 168-174.
Bani-Hani, K.E., N.M. Almasri, Y.S. Khader, F.M. Sheyab, and H.N. Karam, Combined evaluation of expressions of cyclin E and p53 proteins as prognostic factors for patients with gastric cancer. Clinical cancer research, 2005. 11(4): p. 1447-1453.
Irodi, A., T. Rye, K. Herbert, M. Churchman, C. Bartos, M. Mackean, et al., Patterns of clinicopathological features and outcome in epithelial ovarian cancer patients: 35 years of prospectively collected data. BJOG: An International Journal of Obstetrics & Gynaecology, 2020. 127(11): p. 1409-1420.
Abuetabh, Y., H.H. Wu, C. Chai, H. Al Yousef, S. Persad, C.M. Sergi, et al., DNA damage response revisited: the p53 family and its regulators provide endless cancer therapy opportunities. Experimental & Molecular Medicine, 2022. 54(10): p. 1658-1669.
Murnyák, B. and T. Hortobágyi, Immunohistochemical correlates of TP53 somatic mutations in cancer. Oncotarget, 2016. 7(40): p. 64910.
Liu, J., W. Li, M. Deng, D. Liu, Q. Ma, and X. Feng, Immunohistochemical determination of p53 protein overexpression for predicting p53 gene mutations in hepatocellular carcinoma: a meta-analysis. PLoS One, 2016. 11(7): p. e0159636.
Oien, D.B. and J. Chien, TP53 mutations as a biomarker for high-grade serous ovarian cancer: are we there yet? Translational Cancer Research, 2016. 5(Suppl 2).
Sui, L., Y. Dong, M. Ohno, K. Sugimoto, Y. Tai, T. Hando, et al., Implication of malignancy and prognosis of p27kip1, cyclin E, and cdk2 expression in epithelial ovarian tumors. Gynecologic oncology, 2001. 83(1): p. 56-63.
Hamdi, E.A.-W. and S.H. Saleem, P53 expression in ovarian tumors:(an immunohistochemical study). Annals of the College of Medicine Vol, 2012. 38(2).
Karst, A.M., P.M. Jones, N. Vena, A.H. Ligon, J.F. Liu, M.S. Hirsch, et al., Cyclin E1 deregulation occurs early in secretory cell transformation to promote formation of fallopian tube–derived high-grade serous ovarian cancers. Cancer research, 2014. 74(4): p. 1141-1152.
Skirnisdottir, I. and T. Seidal, Association of p21, p21 p27 and p21 p53 status to histological subtypes and prognosis in low-stage epithelial ovarian cancer. Cancer Genomics & Proteomics, 2013. 10(1): p. 27-34.
Müller, W., T. Noguchi, H.C. Wirtz, G. Hommel, and H.E. Gabbert, Expression of cell‐cycle regulatory proteins cyclin D1, cyclin E, and their inhibitor p21 WAF1/CIP1 in gastric cancer. The Journal of pathology, 1999. 189(2): p. 186-193.
Kim, K.K., J.C. Shim, and J.R. Kim, Overexpression of p21, cyclin E and decreased expression of p27 in DMBA (7, 12‐dimethylbenzanthracene)‐induced rat ovarian carcinogenesis. Pathology international, 2003. 53(5): p. 291-296.
Schraml, P., C. Bucher, H. Bissig, A. Nocito, P. Haas, K. Wilber, et al., Cyclin E overexpression and amplification in human tumours. The Journal of Pathology: A Journal of the Pathological Society of Great Britain and Ireland, 2003. 200(3): p. 375-382.
Rosenberg, E., R.I. Demopoulos, A. Zeleniuch–Jacquotte, H. Yee, J. Sorich, J.L. Speyer, et al., Expression of cell cycle regulators p57KIP2, cyclin D1, and cyclin E in epithelial ovarian tumors and survival. Human pathology, 2001. 32(8): p. 808-813.
Rosen, D.G., G. Yang, M.T. Deavers, A. Malpica, J.J. Kavanagh, G.B. Mills, et al., Cyclin E expression is correlated with tumor progression and predicts a poor prognosis in patients with ovarian carcinoma. Cancer: Interdisciplinary International Journal of the American Cancer Society, 2006. 106(9): p. 1925-1932.
Sawasaki, T., K. Shigemasa, Y. Shiroyama, T. Kusuda, T. Fujii, T.H. Parmley, et al., Cyclin E mRNA overexpression in epithelial ovarian cancers: inverse correlation with p53 protein accumulation. The Journal of the Society for Gynecologic Investigation: JSGI, 2001. 8: p. 179-185.
Allal, A.S., P. Gervaz, and M. Bründler, Cyclin D1, cyclin E, and p21 have no apparent prognostic value in anal carcinomas treated by radiotherapy with or without chemotherapy. British journal of cancer, 2004. 91(7): p. 1239-1244.

Table 1: Correlation of p53 expression with malignant progression in ovarian tumors

Malignant progression	Total	P53 expression
Malignant progression	Total	Negative (%)	Weak + (%)	Strong ++ (%)

Benign	15	9 (60)	6 (40)	0
Borderline	12	3 (25)	9 (75)	0
Malignant	45	14 (31.11)	15 (33.33)	16 (35.56)
Total	72	26 (36.11)	30 (41.67)	16 (22.22)*
* P value = 0.002

Table 2: Correlation of cyclin E expression with malignant progression in ovarian tumors

Malignant progression	Total	Cyclin E expression
Malignant progression	Total	Negative (%)	Weak + (%)	Strong ++ (%)

Benign	15	9 (60)	6 (40)	0
Borderline	12	1 (8.33)	6 (50)	5 (41.67)
Malignant	45	11 (24.44)	20 (44.44)	14 (31.11)
Total	72	21 (29.17)	32 (44.44)	19 (26.39)*

Table 3: Correlation of p53 expression with clinicopathological parameters of 34 patients with epithelial ovarian cancer

Parameter

Total

P53 expression

P-value

Negative (%)

Weak + (%)

Strong ++ (%)

Age

< 50

≥ 50

14

20

4 (28.57)

3 (15)

6 (42.86)

8 (40)

4 (28.57)

9(45)

NS

Stage

I/II

III/IV

18

16

6 (33.33)

1 (6.25)

9 (50)

5 (31.25)

3 (16.67)

10 (62.5)

0.015

Grade

I

II

III

5

12

17

2 (40)

2 (16.66)

3 (17.64)

2 (40)

5(41.67)

7(41.18)

1 (20)

5(41.67)

7(41.18)

NS

Histological type

Serous cancer

Mucinous/others

20

14

3 (15)

4 (28.57)

8(40)

6(42.86)

9(45)

4 (28.57)

NS

NS (not significant, P-value > 0.05)

Table 4: Correlation of cyclin E expression with clinicopathological parameters of 34 patients with epithelial ovarian cancer

Parameter

Total

Cyclin E expression

P-value

Negative (%)

Weak + (%)

Strong ++ (%)

Age

< 50

≥ 50

14

20

4 (28.6)

3 (15)

7 (50)

8(40)

3 (21.4)

9(45)

NS

Stage

I/II

III/IV

18

16

4 (22.22)

3(18.75)

8(44.44)

7(43.75)

6(33.33)

6(37.5)

NS

Grade

I

II

III

5

12

17

1 (20)

4 (33.33)

2(11.76)

3 (60)

4 (33.33)

8 (47.06)

1 (20)

4 (33.33)

7 (41.18)

NS

Histological type

Serous cancer

Mucinous/others

20

14

2 (10)

5 (35.71)

6 (30)

9(64.29)

12(60)

0 (0)

0.001

NS (not significant, P-value >0.05)

Table 5: Association between p53 and cyclin E expression in 72 ovarian tumor tissues

	P53 expression			Total	P-value
	Negative	Weak +	Strong ++	Total	P-value
Cyclin E					*P = 0.019*
Negative	12	8	1	21
Weak +	12	11	9	32
Strong ++	2	11	6	19
Total	26	30	16	72

No competing interests reported.

Cyclin E and p53: The Dynamic Duo in Ovarian Tumor Pathogenesis

Status:

Version 1

Abstract

Figures

Introduction

Materials And Methods

Results

Discussion

Abbreviations

Declarations

References

Tables

Additional Declarations

Status:

Version 1