ESMO Congress 2023 | OncologyPRO

Abstract 967P

Background

HCC is a primary malignant liver disease usually presenting with single or multiple nodules developing from underlying chronic hepatitis or cirrhosis. The Polycomb group (PcG) proteins and DNA methylation systems are epigenetic systems involved in hereditary gene activation inhibition. These epigenetic systems are involved in regulating gene expression and are closely related to the development of HCC. EZH2 is a functional enzymatic component of Polycomb Repressive Complex 2 (PRC2). The inhibition of tumor suppressor genes by EZH2 has been observed, and impeding the activity of EZH2 has been shown to decelerate tumor growth. According to some studies, EZH2 expression is associated with aggressive tumor behavior, a poor prognosis, and a poor response to treatment. The goal was to determine if EZH2 expression levels in HCC are of prognostic significance.

Methods

We picked 103 patients who had pathological diagnoses between 2011-2019. Retrospective screenings were done. EZH2 was checked with immunohistochemistry. Survival and treatment responses were analyzed statistically.

Results

89 (86.4%) patients were male, and 14 (13.6%) were female. The median age of the patients was 68 (min19- max 89). 1% and above was considered positive. Immunohistochemically, EZH2 showed positive staining in 45 (43.7%) patients, and no staining was observed in 58 (56.3%) patients. The patients' median progression-free survival (mPFS) in the positive group was 5 months, while the mPFS of the negative group was 9 months (p=0.012). Based on comprehensive survival analysis, 35 of 45 patients in the positive group had died, and 10 were still alive. In the negative group, 36 patients died, and 22 survived. In the positive group, the median overall survival (mOS) was 8 months; in the negative group, it was 27 months (p=0,007). In our study, EZH2 had prognostic significance for progression-free and overall survival. Furthermore, an increase in EZH2 expression level was associated with a poor prognosis.

Conclusions

We established the prognostic significance of EZH2 for HCC. These findings could lead to new therapeutic strategies (e.g. tazemetostat) for treating and managing HCC. A greater understanding of EZH2's role in HCC requires further research.