Glutamine synthetase expression levels as a prognostic biomarker in fibrolamellar hepatocellular carcinoma at the National Institute of Cancerology of Mexico.

e16168 Background: Fibrolamellar hepatocellular carcinoma is a rare neoplasm with a clinicopathologic behavior that differs from conventional hepatocellular carcinoma. Most cases are diagnosed at an advanced stage. Treatment based on surgery or liver transplantation is the only potentially curative approach. According to US epidemiological registries, fibrolamellar hepatocellular carcinoma represents less than 1% of primary liver malignancies, and according to Mexican registries, it represents 5.8% of liver tumors. The search for biomarkers in the era of precision oncology to establish prognostic and predictive factors is considered fundamental for personalized treatment. There is only one study on glutamine synthetase expression in patients with liver disease from which the review on glutamine synthetase expression as a prognostic factor in hepatocellular carcinoma were derived. However, to our knowledge, there is no data on the determination of glutamine synthetase expression levels and fibrolamellar hepatocellular carcinoma. Methods: Retrospective study. Included patients with fibrolamellar hepatocellular carcinoma treated at the National Cancer Institute in Mexico between 2006-2023. Statistical analysis: X 2 and t-test, Kaplan Meier, Log Rank, and Cox Regression. Statistical significance differences were assessed when p was bilaterally < 0.05. Results: A total of 31 patients with diagnosis of fibrolamellar hepatocellular carcinoma were included in the study. Most of the patients were male 51% (n = 16) with a median age of 25 years (16 - 58). According to functional status, 54% (n = 17) of patients reported ECOG 1 and stage IV disease were present in 64% (n = 20). Regarding the characteristics of the population studied, the median range of alpha-fetoprotein (AFP) was 95.9 (0-1608), albumin 3.3 (1.8-4.8), for tumor size 12 (2-21). Regarding treatment modalities 22% (n = 7) were taken to initial surgery, 10% (n = 3) to a locorregional procedure and 58% (n = 18) to systemic therapy which the two most commonly used were capecitabine in 22% (n = 7) and sorafenib in 13% (n = 4). Glutamine synthetase expression was positive in 90% (n = 28). The median OS in the entire population was 17.5 months (7-27). In non-expressing subjects was 70 months (0-150) while in expressing subjects was 13 months (7-20) (p = 0.125). Conclusions: In conclusion, glutamine synthetase expression are increased in fibrolamellar hepatocellular carcinoma. This study provides crucial insights to suggest a potential prognostic role on this biomarker, requiring further studies and efforts to improve outcomes in this young patients.