Abstract 2695: A higher percentage of M2 macrophages in non-tumor part predict the tumor recurrence in patients with hepatocellular carcinoma after surgical resection

Abstract

Abstract The primary hurdle in improving outcomes for hepatocellular carcinoma (HCC) patients after curative treatment is the high early recurrence rate. The existing literature indicates the presence of type 2 macrophages (M2), renowned for their immunosuppressive capabilities, has been implicated in creating a microenvironment conducive to tumor growth and recurrence. However, the intricate interplay involving M2 macrophages and the recurrence of HCC is underexplored. Therefore, we conducted an analysis involving HCC patients who underwent hepatectomy at our hospital between 2013 and 2017. We collected samples from both the tumor and non-tumor regions and subjected them to bulk RNA sequencing for comprehensive molecular profiling. The proportion of immune cells was calculated by CIBERSORTx.In our study, we enrolled fifty patients, with sixty percent presenting with cirrhosis and seventy-three percent having viral hepatitis. Twenty-three patients experienced tumor recurrence, with a median time to recurrence of 12.6 months. First, we found no correlation between five TIMR subtypes defined by TIMELASER (Xue R, Nature, 2022) and recurrence. However, as for the proportions of immune cell, a significantly lower NK/Treg ratio (p= 0.0163) and high within the resected tumor section in recurrent group was found. On the other hand, the ratio of M2 macrophages to total macrophages (M2/M) was significantly higher within the non-tumor region in patients experiencing tumor recurrence after hepatectomy (p=0.0357). Furthermore, the expression of the ACGT2 gene in non-tumor part, which strongly correlates with Treg function, was significantly higher (p=0.0056) in recurrent group. In addition, the innate T cells score was increased in non-tumor pat in recurrent group but with borderline significance (p=0.0628). However, in multivariable analysis, only a higher M2/M ratio within the non-tumor region (HR 3.756, p=0.0072) were identified as independent risk factors for tumor recurrence. We also found that patients with a higher M2/M ratio had a lower percentage of cirrhotic patients (p=0.0049) and less association with TIME-IA (immune activation) subtype of HCC by TIMELASER classification (p=0.0030). In conclusion, a higher M2/M ratio within the non-tumor region predict the tumor recurrence in patients with hepatocellular carcinoma. Citation Format: Po-Ting Lin, Wei-Ting Ku, Tsung-Han Wu, Cheng-Heng Wu, Chan-Keng Yang, Wei Teng, Yung-Chang Lin, Chun-Yen Lin. A higher percentage of M2 macrophages in non-tumor part predict the tumor recurrence in patients with hepatocellular carcinoma after surgical resection [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2695.