European Journal of Cardiovascular Medicine

Gynecological cancers remain a major cause of morbidity and mortality among women worldwide. After cervical cancer, ovarian cancer is a predominant cause of mortality among women, largely due to its insidious onset and diagnosis at advanced stages.[1] The ovaries are paired reproductive organs derived from the genital ridges, similar to the embryological origin of the testes. The complex anatomy and unique physiology of the ovary, which is characterized by continuous cyclical changes from adolescence to menopause, give rise to multiple cell types, each possessing the potential for neoplastic transformation.[2] Owing to their deep pelvic location, ovarian tumors can enlarge considerably without producing early symptoms, delaying clinical detection.

Consequently, nearly 70% of patients presents with  metastatic spread beyond the ovaries, and approximately 60% have disease extending  beyond the pelvis at the time of diagnosis. The lifetime risk of developing an ovarian neoplasm is estimated to be between 5% and 7%.[3] Approximately 80% of ovarian tumors are benign, presenting as cystic, solid, or mixed lesions and generally associated with a favorable prognosis, while the remaining 20% are malignant.[4] Ovarian tumors comprise a heterogeneous group, including epithelial, sex cord–stromal, and germ cell tumors. Among these, epithelial ovarian carcinoma is the most common and represents a leading cause of death, with clinical manifestations such as abdominal pain, pelvic discomfort, urinary frequency, abnormal bleeding, weight loss, and fatigue.

Survival outcomes in ovarian cancer are influenced by several factors, including patient age, race, histologic subtype, tumor grade, FIGO stage, residual disease, serum CA-125 levels, and performance status at diagnosis.[5] However, these clinicopathological parameters alone are insufficient to fully elucidate the complex biological behavior of ovarian cancer, highlighting the need for more objective prognostic markers. Recent research has focused on molecular biomarkers, particularly p53 and Ki-67, to better understand tumor biology.

Mutations in p53 occur early in ovarian carcinogenesis and may initiate tumor progression, thereby contributing to tumor development, invasion, and metastasis in surface epithelial ovarian cancers.[6] Ki-67, a nuclear protein expressed during active phases of the cell cycle, serves as a reliable marker of cellular proliferation and is particularly useful in identifying high-grade tumors with aggressive behaviour.[5]

Aims and Objectives

The present study aims to evaluate the histomorphological diversity of surface epithelial ovarian neoplasms and assess the diagnostic efficacy of the immunohistochemical markers p53 and Ki-67 in distinguishing borderline and malignant epithelial tumors. The objectives include studying the clinicopathological characteristics of surface epithelial ovarian tumors, classifying them based on histopathological type and grade, and analyzing the expression patterns of p53 and Ki-67 to aid in accurate diagnosis and prognostic assessment.

Study Design The present study was conducted in the Department of Pathology, in collaboration with the Department of Obstetrics and Gynecology, at Rangaraya Medical College (RMC), Kakinada, from November 2022 to November 2024. A total of 150 cases of surface epithelial ovarian tumors were included in the study based on predefined inclusion and exclusion criteria. Inclusion and Exclusion Criteria Ovarian tumors diagnosed as surface epithelial tumors on histopathological examination were included in the study, and immunohistochemistry performed on selected cases that were histopathologically categorized as borderline and malignant surface epithelial lesions. Tumors of the ovary other than surface epithelial tumors, non-neoplastic ovarian lesions, and inadequately fixed specimens were excluded from the study. Immunohistochemical analysis was carried out in 31 selected borderline and malignant cases using p53 (ZR153) and Ki-67 (MIB1) antibodies on tissue specimens preserved in neutral buffered formalin. Data Collection Tools Data collection was carried out using histopathological examination and immunohistochemical techniques as the primary tools. Formalin-fixed, paraffin-embedded ovarian tissue specimens were processed for routine hematoxylin and eosin (H&E) staining to assess tissue architecture and cytomorphological features. Immunohistochemistry was employed as an adjunct diagnostic tool using monoclonal antibodies against p53 (ZR153) and Ki-67 (MIB1) to evaluate tumor suppressor gene alterations and cellular proliferative activity, respectively. These tools enabled detailed assessment of histomorphology, tumor classification, and biomarker expression in surface epithelial ovarian tumors. Data Collection Procedure Tissue specimens preserved in neutral buffered formalin were processed routinely to prepare paraffin blocks, from which 4–6 µm thick sections were obtained. Sections were stained with H&E following standard protocols to evaluate nuclear and cytoplasmic morphology. Immunohistochemical staining was performed manually using the peroxidase–antiperoxidase (PAP) method. After deparaffinization, rehydration, and antigen retrieval with sodium citrate buffer (pH 6.0), endogenous peroxidase activity was blocked. Sections were incubated with primary antibodies against p53 or Ki-67, followed by appropriate secondary antibodies and enzyme complexes. Visualization was achieved using diaminobenzidine (DAB) chromogen, and slides were counterstained with hematoxylin, dehydrated, cleared, and mounted. Interpretation of p53 expression was categorized as wild-type or mutant patterns, while Ki-67 labeling index was graded as negative, low, or high based on the percentage of positively stained nuclei. Statistical Analysis Data obtained from the study were entered into Microsoft Excel and analyzed using appropriate statistical software. Categorical variables such as age distribution, clinical presentation, laterality, gross morphology, histological subtypes, and immunohistochemical expression of p53 and Ki-67 were expressed as frequencies and percentages. Associations between tumor behavior (benign, borderline, malignant) and immunohistochemical markers were assessed using the Chi-square test. The relationship between the Ki-67 index and FIGO stage was also evaluated using Chi-square analysis. A p-value of less than 0.05 was considered statistically significant. Results were interpreted in conjunction with clinicopathological findings to assess diagnostic and prognostic relevance.

Table 1 shows that benign surface epithelial ovarian tumours were most common in the 31–40-year age group, while borderline and malignant tumours predominantly occurred in the 41–50-year age group. Notably, no borderline or malignant tumours were observed below 30 years of age, indicating increasing malignant potential with advancing age.

Table 2 illustrates that the most common presenting symptom was mass per abdomen, followed by abdominal pain. Menstrual abnormalities were less frequent, indicating that many ovarian tumours present with non-specific abdominal symptoms.

Table 3 shows a predominant unilateral involvement of ovarian tumours, with the right ovary more commonly affected than the left. Bilateral tumours constituted a small proportion of cases.

Table 4 demonstrates that benign tumours were predominantly small, cystic, and unilateral. In contrast, malignant tumours more frequently exhibited larger size, mixed or solid consistency, highlighting the diagnostic importance of solid components in predicting malignancy.

Table 5 shows that serous tumours were the most common histological subtype, followed by mucinous tumours. Endometrioid tumours were rare and exclusively malignant in the present study.

Table 6 illustrates that all borderline tumours expressed wild-type p53 with low proliferative activity. Malignant serous tumours showed mutant p53 expression with a high Ki-67 index, whereas malignant mucinous tumours showed mutant p53 but retained a low proliferative index.

Table 7 shows that low Ki-67 index was predominantly seen in early-stage tumours, whereas high Ki-67 index was more frequent in advanced stages, confirming the association between increased proliferative activity and tumour progression.

Ovarian cancer remains a significant cause of gynecological morbidity and mortality worldwide, largely due to its heterogeneous nature and late clinical presentation. Understanding the demographic profile, histomorphological spectrum, and immunohistochemical behavior of ovarian tumors is essential for accurate diagnosis, prognostication, and therapeutic planning. The present study evaluates surface epithelial ovarian tumors with particular emphasis on p53 and Ki-67 expression and correlates these findings with clinicopathological parameters.

In the present study, surface epithelial tumors constituted 91.4% of all ovarian neoplasms, confirming that they are the most common category of ovarian tumors. This observation is consistent with previous studies by Choudary et al.[7] Lavanya et al.[8] and Ranjani et al.[9] all of whom reported a predominance of surface epithelial tumors. The higher incidence in our study may reflect improved diagnostic practices and increased surgical interventions at tertiary care centers.

Age distribution analysis revealed that benign tumors were most common in the 31–40 years age group, while borderline and malignant tumors showed a peak incidence in the 41–50 years age group. Notably, no borderline or malignant tumors were observed below 30 years of age. These findings are comparable with studies by Ranjani et al.[9] whereas Mohapatra et al.[10] and Ruby et al.[11] reported a slightly higher age range (41–60 years) for malignant tumors. The increased incidence of malignancy in the fifth decade highlights the need for vigilant screening in peri-menopausal women.

Clinically, the most common presenting symptoms in benign tumors were  abdominal pain and menstrual irregularities, whereas  mass per abdomen was the predominant symptom in borderline and malignant tumors. Similar symptom patterns were observed in studies by Vohra et al.[12] Ruby et al.[11] and Ranjani et al.[9] The variability in symptom presentation underscores the diagnostic challenge posed by ovarian tumors and emphasizes the importance of thorough clinical evaluation.

Laterality assessment showed that 93% of tumors were unilateral, with the right ovary more frequently involved than the left. Bilateral tumors accounted for only 7% of cases and were predominantly of serous histology. These findings are in agreement with studies by Ranjani et al.[9] Bilaterality in mucinous tumors necessitates careful exclusion of metastatic disease, particularly from the gastrointestinal tract.

Gross examination revealed that benign tumors were predominantly cystic, smaller than 10 cm, and unilateral. In contrast, malignant tumors frequently showed larger size, mixed solid-cystic architecture, or pure solid areas. Pure solid tumors were exclusively malignant in the present study. Borderline tumors displayed intermediate features, emphasizing the importance of extensive sampling to rule out invasive foci. These observations align with the findings by Ranjani et al.[9] supporting the role of gross morphology as a preliminary indicator of malignancy.

Histologically, serous tumors were the most common subtype (56.7%), followed by mucinous (42%) and endometrioid tumors (1.3%). No clear cell or Brenner tumors were encountered. Similar distributions have been reported by Swathi et al.[13] and Ranjani et al.[9] although variations exist across studies, possibly due to geographic and genetic differences. Serous tumors continue to predominate globally, reinforcing their clinical significance.

Immunohistochemical analysis demonstrated a strong association between p53 mutation and malignant serous tumors. All serous borderline tumors exhibited wild-type p53 expression, whereas all malignant serous tumors showed mutant p53 expression (either overexpression or null pattern). This finding is consistent with earlier studies by Rekha et al.[14] Ranjani et al.[9] and Ranjan et al.[15] confirming the role of p53 mutation in serous carcinogenesis.

In mucinous tumors, all borderline tumors showed wild-type p53 expression, while malignant tumors exhibited mutant p53 expression, predominantly in a subclonal cytoplasmic pattern. This intratumoral heterogeneity may be related to terminal differentiation and transcriptional downregulation, as suggested in previous studies. Endometrioid carcinomas in the present study retained wild-type p53 expression, reflecting a distinct molecular pathway.

The chi-square analysis for p53 expression yielded a p-value of 0.0696, indicating a trend toward statistical significance. Although not meeting the conventional threshold, this finding suggests a biologically relevant association that may reach significance with larger sample sizes.

Ki-67 immunohistochemistry showed a statistically significant association with tumor subtype (p = 0.0009). A High Ki-67 index was predominantly observed in malignant serous tumors, particularly those presenting at advanced FIGO stages, whereas borderline tumors and mucinous tumors demonstrated low proliferative indices. These findings corroborate earlier observations by Rekha et al.[14] and Mohapatra et al.[10] highlighting Ki-67 as a reliable marker of tumor aggressiveness.

Correlation analysis between the Ki-67 index and FIGO staging revealed that tumors with low Ki-67 expression were mostly confined to Stage I, while high Ki-67 expression was associated with advanced stages (II and III). This supports the prognostic value of Ki-67 in predicting tumor behavior and clinical outcomes.

A single case of ovarian carcinosarcoma was identified, exhibiting biphasic epithelial and mesenchymal components with p53 overexpression and high a Ki-67 index in both components. These findings support the monoclonal origin theory and align with emerging evidence suggesting that carcinosarcomas may represent an aggressive variant of high-grade serous carcinoma.

Limitations

The present study has certain limitations that should be acknowledged. Being a single-center study, the findings may be influenced by institutional factors such as local patient demographics, referral patterns, and treatment protocols, thereby limiting their generalizability to wider populations. The lack of long-term follow-up data restricts assessment of important outcomes including recurrence rates, survival patterns, and long-term treatment efficacy. Additionally, the inclusion of only surgically managed patients may have introduced selection bias by excluding individuals with advanced or inoperable disease, which could affect the overall applicability and accuracy of the results. These limitations necessitate cautious interpretation of the findings and underscore the need for larger, multi-center studies with extended follow-up to validate the observations.

The present study provides a comprehensive overview of the demographic and clinicopathological profile of ovarian tumors, emphasizing the significance of age distribution, tumor laterality, and histopathological features in their diagnosis. Serous and mucinous tumors were the most prevalent subtypes across benign, borderline, and malignant categories. Immunohistochemical evaluation revealed that mutant p53 expression and a high Ki-67 index were predominantly associated with malignant serous tumors, reflecting aggressive biological behavior and poor prognosis, whereas borderline tumors consistently demonstrated wild-type p53 expression with low Ki-67 proliferation indices, indicative of a more favorable prognosis. The combined assessment of p53 and Ki-67 thus offers valuable insight into tumor behavior and progression and may aid clinicians in refining diagnostic accuracy, prognostic stratification, and therapeutic decision-making, ultimately contributing to improved patient outcomes.

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[8]           Rajagopal L, Raja V, Arunachalam S, et al. Ki – 67 and p53 – Novel prognostic biomarkers in surface epithelial ovarian tumors. National Journal of Basic Medical Sciences 2018;8(4):199-208.

[9]           Ranjani S, Lakshmi CV, Parvathi G, et al. Clinicopathological analysis of ovarian tumors and p53 expression in surface epithelial tumors at a tertiary care center. Int J Acad Med Pharm 2024;6(1):379-84.

[10]         Mohapatra I, Harshini N, Samantaray SR, et al. Immunohistochemical expression of P53 and Ki-67 on epithelial tumors of ovary. International Journal of Reproduction, Contraception, Obstetrics and Gynecology 2021;10(3):1005-10.

[11]         Jaiswal R, Bohara S, Bhattacharya AB, et al. Clinicohistopathological features and immunohistochemical expression patterns of p53 in epithelial ovarian tumours: a cross-sectional study. National Journal of Laboratory Medicine 2025;13(1):PO41-6.

[12]         Vohra NV. Immunohistochemical expression of KI – 67 in ovarian surface epithelial tumors and its correlation. European Journal of Molecular & Clinical Medicine 2020;7(1):90-4.

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[14]         Verma R, Gupta P, Tiwari N, et al. Histological grade, CA 125 levels and IHC expression of ER/ PR, her-2/neu, p53 and ki 67 markers in epithelial ovarian neoplasms: a correlative study. Int J of Adv Res 2017;5:235-54.

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