Abstract 4964: Associations between hepatitis etiology and immune cell infiltration in or around hepatocellular carcinoma

Abstract

Abstract Background: Previous studies have demonstrated that the abundance of immune cells may be associated with hepatocellular carcinoma (HCC) prognosis. Because HCC has various hepatitis etiologies, we studied the associations between hepatitis etiology and regional lymphocyte infiltration at and beside the tumor. Methods: We collected tumor samples from patients who received curative surgery for HCC. Immunohistochemical staining was performed on tissue slides, which were then scanned using TissueFAXS v4.2 and analyzed using HistoQuest v4.0 (both from TissueGnostics Inc.). We calculated the amount of total T cells (CD3 positive), CD8 T cells (CD8 positive), and macrophages (CD68 positive) inside the tumor (IT), at the tumor margin (TM), and outside the tumor (OT). For analysis at IT and TM, the whole area were examined. For analysis at OT, only the five areas with the highest cell density at the low power fields were analyzed. For each area, we defined low and high cell density according to the median values. We then explored the associations of these cell distributions and HCC etiologies or prognosis. Results: We included HCC samples from 120 patients. Among them, 76 (63%) had hepatitis B virus (HBV) infection, 28 (23%) had hepatitis C virus infection, 14 patients had neither infections, and 1 patient had both HBV and HCV infection. The amount of total T cells (p < 0.001), CD8 T cells (p < 0.001), and total macrophages (p < 0.001) were all significantly higher at TM than at IT. HCV-positive tumors, compared to HBV-positive tumors had more total T cells inside (p = 0.040) and outside the tumors (p < 0.001), but similar total T cells at the margin. On the contrary, the amount of CD8 T cells and total macrophages were similar between HBV-positive and HCV-positive tumors at IT, TM, and OT. Samples of 112 patients included both IT and TM area. Using CD8 cell counts for classification, 40 (33%) were IThighTMhigh, 16 (13%) were ITlowTMhigh, 42 (35%) were ITlowTMlow, and 14 (12%) were IThighTMlow. Patients with ITlowTMlow tumors tended to have poorer overall survival than other patients (p = 0.085), but patients with IThighTMhigh, ITlowTMhigh, and IThighTMlow tumor had similar prognosis (p = 0.770). Hepatitis virus infected tumors were significantly less likely to be ITlowTMlow than hepatitis virus uninfected tumors (33% vs. 69%, p = 0.010); HBV-infected and HCV-infected tumors had similar percentages of ITlowTMlow tumors (68% vs. 65%, p = 0.837). Conclusions: HCV infection was associated with higher total T cell infiltration inside and outside the tumors. Hepatitis virus uninfected tumors were more likely to have low CD8 cells both inside and at the margin of HCC. Citation Format: Yu-Yun Shao, Min-Shu Hsieh, Yun-Ting Tsai, Ying-Chun Shen, Zhong-Zhe Lin, Ann-Lii Cheng, Chih-Hung Hsu. Associations between hepatitis etiology and immune cell infiltration in or around hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4964.