Abstract

Background: Ocular Surface Squamous Neoplasia (OSSN) encompasses a spectrum of lesions ranging from Conjunctival Intraepithelial Neoplasia (CIN) to Squamous Cell Carcinoma (SCC). Accurately determining the degree of malignancy and the potential for progression remains a diagnostic challenge in pathology. The TP53 gene, which encodes the p53 protein, is a critical tumor suppressor gene frequently mutated by ultraviolet (UV-B) radiation - the primary risk factor for OSSN. Objectives: To describe the clinicopathological characteristics and p53 expression of CIN1 cases, to investigate the association between p53 expression and clinicopathological features, and to compare p53 expression in CIN1 with that in normal conjunctival tissue. Materials and methods: A cross-sectional descriptive study was conducted on 25 cases of CIN 1, including 9 cases with normal conjunctival tissue samples, at the Ho Chi Minh City Eye Hospital from 2022 to 2024. p53 expression was evaluated by immunohistochemistry (IHC) and classified into two patterns: wild-type and mutant-type, with the following staining categories: scattered expression, overexpression, complete absence (null pattern), and cytoplasmic expression. Results: Among 25 cases of CIN 1, the mean age was 45 years, with a male predominance (84%). The majority of cases demonstrated a wild-type p53 expression pattern (76%), while 24% exhibited a mutant-type pattern. The level of p53 expression in the CIN1 group was significantly higher than that in normal conjunctival epithelium (p = 0.002). Conclusions: The study demonstrated a male predominance among patients with CIN 1, and p53 expression in CIN 1 was predominantly of the wild-type pattern. Furthermore, the study showed that the level of p53 expression in the CIN 1 group was significantly higher than that in normal conjunctival epithelium, with a highly statistically significant difference. These findings support the role of p53 as a sensitive biomarker of UV-induced cellular damage, detectable even at the earliest stages of neoplastic transformation.