Progressive p53 Expression in the Histological Spectrum of Cervical Neoplasia
SamuelAyobamiFASOGBON
PhD
1✉EmailSamfash4best@gmail.comFrederickOlusegunAKINBO2
ComfortE.WILLIAMS3
CharlesEgedeUGWU4
Bob-ManuelChinonsoOSUJI5
PeterO.OBAMI6
1Department of Education, Medical Laboratory Science Council of Nigeria (MLSCN)AbujaNigeria
2Medical Laboratory Science Department, Faculty of Basic Medical SciencesUniversity of BeninBenin CityNigeria
3Department of PharmacologyNew York Medical CollegeNew York CityNew YorkUSA
4Paul G. Allen School for Global Health, College of Veterinary MedicineWashington State UniversityPullmanWAUSA
5School of Health and Life SciencesTeesside UniversityMiddlesbrough CityUnited Kingdom
6Department of Cellular PathologyHavering & Redbridge University Hospitals NHS TrustBarking, London CityUnited Kingdom
Samuel Ayobami FASOGBON1*; Frederick Olusegun AKINBO2; Comfort E. WILLIAMS3; Charles Egede UGWU4; Bob-Manuel Chinonso OSUJI5; Peter O. OBAMI6
1Department of Education, Medical Laboratory Science Council of Nigeria (MLSCN), Abuja, Nigeria
2Medical Laboratory Science Department, Faculty of Basic Medical Sciences, University of Benin, Benin City, Nigeria
3Department of Pharmacology, New York Medical College, New York City, New York, USA
4Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
5School of Health and Life Sciences, Teesside University, Middlesbrough City, United Kingdom
6Department of Cellular Pathology, Barking, Havering & Redbridge University Hospitals NHS Trust, London City, United Kingdom
Corresponding Author
Samuel Ayobami FASOGBON, PhD
Samfash4best@gmail.com
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Abstract
Background
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The development of cervical cancer is significantly influenced by the dysregulation of the tumor suppressor p53. While TP53 mutations are frequently present in HPV-independent malignancies, as evidenced by abnormal immunohistochemistry (IHC) patterns, E6-mediated degradation in HPV-associated illness reduces p53 function. This study examined p53 expression in a Nigerian cohort with cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC) to elucidate its function in lesion progression.Methods
Two hundred cervical specimens (CIN I–III and SCC) that were archived as formalin-fixed paraffin-embedded (FFPE) were recovered. For histological confirmation, sections (3 µm) were stained with hematoxylin–eosin (H&E). Then, p53 IHC was performed using the avidin–biotin complex method with microwave antigen retrieval. Proportion and intensity were combined to create a semi-quantitative score (0–6) for the expression. Types: low (1–3), high (4–6), and negative (0). In SPSS v16, associations with age and grade were examined using χ².
Results
High levels of p53 expression were seen in 60.9% of SCC and 46.6% of CIN. CIN I (20.9%), CIN II (70.2%), CIN III (46.3%), and SCC (60.9%) are the grades. There was a significant correlation (p < 0.05) between expression and lesion severity.
Conclusion
p53 expression rises with the severity of the dysplasia, indicating that it may be used as an auxiliary biomarker of the development of cervical neoplasia. Combining pattern-based p53 interpretation, p16/Ki-67 dual-stain, and HPV genotyping may improve its diagnostic and prognostic utility.
Keywords:
Cervical intraepithelial neoplasia
p53
squamous cell carcinoma
immunohistochemistry
biomarker
human papillomavirus
tumor suppressor genes
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Introduction
A significant public health concern is still cervical cancer, especially in sub-Saharan Africa, where the disease burden is high and screening coverage is poor [1, 2]. Persistent high-risk HPV infection is the main histological factor responsible for the development of cervical intraepithelial neoplasia (CIN) to invasive cancer. Cell-cycle regulation and genomic stability are compromised by the viral oncoproteins E6 and E7, which interfere with the p53 and RB pathways, respectively.
Cervical squamous lesions have been reclassified into HPV-associated and HPV-independent pathways in the 5th edition of the WHO classification. Despite being less frequent, HPV-independent squamous carcinomas have worse prognoses and are distinguished by abnormal p53 IHC patterns and frequent TP53 mutations [3]. The necessity to more precisely identify p53 expression in CIN and aggressive cancer is highlighted by this distinction.
An effective method for examining the p53 protein status in archival material is immunohistochemistry (IHC). Wild-type (patchy/variable) and aberrant (diffuse overexpression, complete absence/null, or cytoplasmic) are distinguished by pattern-based interpretation [4].
Even though p53 is not included in standard screening algorithms, it could be useful for understanding the biology of diseases and for supplementary diagnostics, particularly in cases where HPV-independent illness is suspected. The importance of other biomarkers is also highlighted by recent research; for instance, Fasogbon & Akinbo [1] found that the expression of the vitamin D receptor (VDR) gradually decreases with increasing CIN grades, supporting the idea that the tumor suppressor pathway is disrupted.
This study adds local evidence to the global understanding of cervical tumor suppressor biology by examining the expression profile of p53 across CIN grades and SCC in a Nigerian cohort.
Materials and Methods
Study design and sample selection:
Two hundred archival FFPE cervical tissue blocks diagnosed at Lagos University Teaching Hospital between 2002 and 2016 were the subject of a retrospective, cross-sectional analysis. Invasive SCC and CIN I, CIN II, and CIN III cases were among them. Sufficient tissue, a verified histological diagnosis, and the availability of clinical age data are requirements for inclusion. Blocks with inadequate preservation or unclear diagnoses are excluded.
Case type | n tested | High expression (%) | Low expression (%) | p-value |
|---|---|---|---|---|
CIN I | 43 | 9 (20.9) | 34 (79.1) | |
CIN II | 47 | 33 (70.2) | 14 (29.8) | |
CIN III | 41 | 19 (46.3) | 22 (53.7) | |
SCC | 69 | 42 (60.9) | 27 (39.1) | < 0.05 |
Age group (years) | High expression (%) | Low expression (%) | Total (%) |
|---|---|---|---|
≤ 40 | 14 (12.1) | 19 (16.2) | 33 (28.3) |
41–50 | 46 (20.4) | 41 (18.1) | 87 (38.5) |
≥ 50 | 43 (19.0) | 37 (14.2) | 80 (33.2) |
Total | 103 (51.5) | 97 (48.5) | 200 (100) |
Ethical approval:
Granted approval by the Lagos University Teaching Hospital Health Research Ethics Committee (LUTHHREC) on June 18, 2020, under approval number ADM/DCST/HREC/APP/3429. This study complied with the Helsinki Declaration.
Histopathological review:
Sections of 3 µm were cut for every case. To assess lesion adequacy and confirm the diagnosis, one section was stained with H&E.
Immunohistochemistry:
IHC for p53 was carried out using the avidin–biotin complex (ABC) method using a mouse monoclonal anti-p53 antibody. Using microwave heating, antigen retrieval was performed in citrate buffer (pH 6.0) [9]. Primary antibody (1:100, 60 min), secondary antibody, HRP conjugate, and DAB chromogen were treated with the sections. Mayer's hematoxylin was used for counterstaining. Both negative controls (primary antibody deleted) and appropriate positive controls (known p53-positive cancer) were included.
Scoring:
A semi-quantitative assessment of nuclear staining was conducted [13]:
The proportions are as follows: 0 = 0%, 1 = < 30%, 2 = 30–60%, and 3 = > 60%.
• Intensity is denoted by 0 for none, 1 for weak, 2 for moderate, and 3 for strong.
• A + B (0–6) is the final score.
The scores were divided into three categories: low (1–3), high (4–6), and negative (0). To increase reproducibility, two assessors separately examined each slide; disagreements were settled by consensus.
Statistical analysis:
SPSS v16 was used to enter the data. Expression levels were summarized using descriptive statistics. Chi-square was used to look for associations between p53 category and age or histological grade; a p-value of less than 0.05 was deemed statistically significant.
Results
According to Table 1, high p53 expression was seen in 60.9% of SCC and 46.6% of CIN.
SCC (60.9%), CIN I (20.9%), CIN II (70.2%), and CIN III (46.3%) by grade.
Lesion severity and expression had a strong correlation (p < 0.05).
The highest incidence of high expression was found in women between the ages of 41 and 50 (Table 2).
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Figs. 1.4
display representative immunohistochemical pictures that indicate the progression and distribution of p53 expression in CIN I–III and SCC.
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Fig. 1
Immunohistochemistry of mild expression of p53 in CIN I showing dysplastic cells confined to the lower third of the epithelium with brown nuclear staining (x400).
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Fig. 2
Immunohistochemistry of moderate expression of p53 in CIN II showing atypical cells in the lower two-thirds of the epithelium with brown nuclear staining (x400).
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Fig. 3
Immunohistochemistry of strong expression of p53 in CIN III showing full-thickness dysplasia with loss of polarity and strong brown nuclear staining (x400).
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Fig. 4
Immunohistochemistry of strong expression of p53 in squamous cell carcinoma showing nests of malignant squamous cells infiltrating the stroma with diffuse brown nuclear staining (x400).
Discussion
In line with data from Europe, Asia, and Africa [10–12], this study showed a gradual rise in p53 expression from CIN I through SCC. Our results are consistent with the idea of a molecular continuum where histological advancement is accompanied by a progressive deregulation of tumor suppressor pathways.
Biological interpretation
There are differences between HPV-associated and HPV-independent pathways in the processes behind p53 disruption. The increase of wild-type protein under stress or the stabilization of mutant protein may be reflected in p53 upregulation in HPV-associated lesions [14,15]. TP53 mutations are frequently found in HPV-independent carcinomas, which can lead to abnormal IHC patterns including diffuse high positivity or total absence [6,7]. Identifying these patterns can be useful for diagnosis, especially when HPV testing comes back negative.
Comparison with other biomarkers
Biomarker panels work better than individual markers, according to recent studies. The most proven adjuncts for diagnosis and triage are still p16 and ki-67 [8]. In India, Kaur et al. (2025) showed a high correlation between CIN grade and the combined expression of p53 and Ki-67. Concordant overexpression of p16, p53, and Ki-67 was reported in Nigeria by Ogbu et al. (2022), highlighting the significance of these genes in African populations.
In line with the p53 trajectory, our earlier research on the vitamin D receptor (VDR) revealed increasing receptor loss across CIN grades [1]. These results collectively imply that cumulative deactivation of several tumor suppressor mechanisms plays a role in cervical carcinogenesis.
Clinical implications
Although p53 has potential as an auxiliary biomarker in pathology, it is not advised for primary screening. It may help in the following:
Clarification of unclear histology instances is one area.
Comprehending HPV-independent carcinoma, which has a poorer outlook.
Aiding in diagnosis in cases where molecular resources are scarce.
Incorporating p53 into pathology workflows in addition to p16/Ki-67 and HPV DNA tests may improve diagnosis accuracy and help guide treatment plans.
Strengths and limitations
The inclusion of all CIN grades, the comparatively high sample size, and the underrepresented local African data are among its strengths. Retrospective design, lack of HPV type, lack of outcome data, and reliance on semi-quantitative interpretation rather than pattern-based interpretation, which is now advised by WHO/ESMO guidelines, are among the limitations.
Future perspectives
Future studies should:
Use molecular markers and HPV genotyping to more accurately categorize diseases that are not caused by HPV.
Use pattern-based p53 scoring to differentiate expression linked to the wild type from that of the mutant.
Investigate AI-assisted quantification and digital pathology to lessen observer variability.
Perform prospective African cohort studies with clinical follow-up to confirm prognostic significance.
Conclusion
The molecular continuum of cervical carcinogenesis is shown in this study, which shows that p53 expression rises gradually from CIN to invasive squamous carcinoma. Our results, which come from a Nigerian cohort, add to the scant information available from sub-Saharan Africa and highlight the usefulness of p53 as a secondary biomarker as opposed to a main screening method. Although p53 cannot replace HPV testing or p16/Ki-67 dual-stain, it can aid in histopathological grading, especially in lesions that are difficult to diagnose or HPV-independent. To confirm its predictive value and improve risk classification in a variety of groups, future research involving HPV genotyping, pattern-based p53 interpretation, and other biomarkers is required.
Ethics approval and consent to participate
Granted approval by the Lagos University Teaching Hospital Health Research Ethics Committee (LUTHHREC) on June 18, 2020, under approval number ADM/DCST/HREC/APP/3429. According to national regulations, the Ethics Committee exempted the informed consent requirement because this was a retrospective study employing anonymized, archived formalin-fixed paraffin-embedded (FFPE) tissue blocks.
Consent for publication
Not applicable.
Availability of data and materials
This published article already contains the datasets created and examined during the current investigation. The Corresponding author can provide more supporting information upon reasonable request.
Competing interests
The author declares no competing interests.
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Acknowledgement
The authors would like to express their gratitude to Mr. Osiagwu Daniel of the University of Lagos College of Medicine and Dr. Jonathan U. Madukwe of the Cellular Pathology Specialty at the National Hospital Abuja for their technical support of the immunohistochemistry laboratory study. We also sincerely thank Prof. A.A.F. Banjo for his important contribution to tissue diagnostics.
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Funding
This study did not get any special funding.
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Author Contribution
SAF conceived and designed the study, performed immunohistochemistry, carried out data analysis, interpreted results, and drafted the manuscript.FOA provided supervision, contributed to study design, guided interpretation of results, and critically revised the manuscript for important intellectual content.CEW assisted in histopathological review and confirmation of tissue diagnoses.CEU contributed to laboratory support and immunohistochemistry slide preparation.BCO performed statistical analysis, contributed to data interpretation, and supported results validation.POO assisted in manuscript writing, contextual discussion, and final critical review.All authors read and approved the final version of the manuscript.
Frederick Olusegun Akinbo (FOA): Provided supervision, contributed to study design, guided interpretation of results, and critically revised the manuscript for important intellectual content.
Comfort E. Williams (CEW): Assisted in histopathological review and confirmation of tissue diagnoses.
Charles Egede Ugwu (CEU): Contributed to laboratory support and immunohistochemistry slide preparation.
Bob-Manuel Chinonso Osuji (BCO): Performed statistical analysis, contributed to data interpretation, and supported results validation.
Peter O. Obami (POO): Assisted in manuscript writing, contextual discussion, and final critical review.
All authors read and approved the final version of the manuscript.
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Data Availability
This published article already contains the datasets created and examined during the current investigation. The Corresponding author can provide more supporting information upon reasonable request.
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