Abstract Introduction: There is mounting evidence indicating that the co-existence of Human papillomavirus (HPV), and Epstein-Barr virus (EBV) is associated with aggressive and poorly differentiated squamous cell carcinomas (SCC) phenotype. However, there is a paucity of data on the prevalence of EBV in cases of cervical cancer in Southern Nigeria or the effect of both viruses on p53 gene expression among patients diagnosed with cervical cancer. Therefore, this study investigated the prevalence of mutant p53 (mtp53) in single and co-presence of HPV and EBV-LMP1 in invasive and non-invasive cases of cervical cancer in order to determine the role of EBV in cervical carcinogenesis. Methods: This retrospective cohort study included 105 viable archived formalin-fixed paraffin-embedded tissues of cervical cancer, diagnosed between 2016 and 2019 in two tertiary health care facilities in Southern Nigeria. Tissue sections were stained for mtp53, EBV-LMP1, and HPV using the immunohistochemical technique and scored based on staining intensity and documented as 0, +1, +2, and +3. Tissues with scores of 0 and +1 were considered negative whereas those with scores of +2 and +3 were considered positive. Descriptive, Chi-square test and Pearson’s correlation were carried out and statistical significance was set at ≤0.05. Result: The mean age of participants with cervical cancer was 53.32 ± 12.54 years. The prevalence of invasive and non-invasive cases of cervical cancer were 62.9% and 37.1%, respectively. The prevalence of well, moderately, and poorly differentiated cervical cancer were 54.3%, 34.3%, and 11.4%, respectively. The prevalence of single EBV-LMP1, and HPV antigen were 21.0% (n= 21) and 14.2% (n= 15), respectively whereas the prevalence of EBV-LMP1/HPV co-infection was 42.9% (n= 45). The prevalence of HPV/EBV-LMP1 co=presence was high in invasive cervical cancer compared with non-invasive cervical cancer cases (45.5% versus 30.8%) at p= 0.154. The prevalence of mtp53 was higher in EBV-LMP1/HPV co-presence compared with HPV, and EBV-LMP1 mono-presence (80.0%, 60.0%, and 14.3%, respectively) at p= 0.001. Conclusion: This study suggests that EBV increases the risk of cervical carcinogenesis in HPV-infected individuals in Southern Nigeria. Thus, EBV DNA should equally be investigated during HPV testing of suspected cervical cancer cases to identify individuals with poorer prognoses. Citation Format: Jude Okoye, Anthony Ajuluchukwu Ngokere, Charles Chinedum Onyenekwe, Ukpai Eze, Okechi Obioma. The pattern of mutant p53 protein expression in cervical cancer-associated single and co-infection with human papillomavirus and Epstein-Barr virus [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C029.