Hyo Jeong Kang1, Ji-Hye Oh2, Sung-Min Chun3, Deokhoon Kim3, Yeon-Mi Ryu4, Hee Sang Hwang1, Sang-Yeob Kim5, Jihyun An6, Eun Jeong Cho2, Hyeonjin Lee2, Ju Hyun Shim7, Chang Ohk Sung8, Eunsil Yu9. 1. Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. 2. Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea. 3. Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Center for Cancer Genome Discovery, Asan Institute for Life Science, Asan Medical Center, Seoul, Republic of Korea. 4. Asan Institute for Life Science, Asan Medical Center, Seoul, Republic of Korea. 5. Asan Institute for Life Science, Asan Medical Center, Seoul, Republic of Korea; Department of Convergence Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea. 6. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea; Department of Gastroenterology and Hepatology, Hanyang University of Medicine, Guri, Republic of Korea. 7. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Asan Liver Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address: s5854@amc.seoul.kr. 8. Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Department of Medical Science, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea; Center for Cancer Genome Discovery, Asan Institute for Life Science, Asan Medical Center, Seoul, Republic of Korea. Electronic address: co.sung@amc.seoul.kr. 9. Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea; Asan Liver Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address: esyu@amc.seoul.kr.
Abstract
BACKGROUND & AIMS: The immunogenomic characteristics of hepatocellular carcinomas (HCCs) with immune cell stroma (HCC-IS), defined histologically, have not been clarified. We investigated the clinical and molecular features of HCC-IS and the prognostic impact of Epstein-Barr virus (EBV) infection. METHODS: We evaluated 219 patients with conventional HCC (C-HCC) and 47 with HCC-IS using in situ hybridization for EBV, immunohistochemistry, multiplex immunofluorescence staining, and whole exome and transcriptome sequencing. Human leukocyte antigen types were also extracted from the sequencing data. Genomic and prognostic parameters were compared between HCC-IS and C-HCC. RESULTS: CD8 T cell infiltration was more frequent in HCC-IS than C-HCC (mean fraction/sample, 22.6% vs. 8.9%, false discovery rate q <0.001), as was EBV positivity in CD20-positive tumor-infiltrating lymphocytes (TILs) (74.5% vs. 4.6%, p <0.001). CTNNB1 mutations were not identified in any HCC-IS, while they were present in 24.1% of C-HCC (p = 0.016). Inhibitory and stimulatory immune modulators were expressed at similar levels in HCC-IS and EBV-positive C-HCC. Global hypermethylation, and expression of PD-1 and PD-L1 in TILs, and PD-L1 in tumors, were also associated with HCC-IS (p <0.001), whereas human leukocyte antigen type did not differ according to HCC type or EBV positivity. HCC-IS was an independent factor for favorable recurrence-free survival (adjusted hazard ratio [aHR] 0.23; p = 0.002). However, a subgroup of tumors with a high density of EBV-positive TILs had poorer recurrence-free (aHR 25.48; p <0.001) and overall (aHR 9.6; p = 0.003) survival, and significant enrichment of CD8 T cell exhaustion signatures (q = 0.0296). CONCLUSIONS: HCC-IS is a distinct HCC subtype associated with a good prognosis and frequent EBV-positive TILs. However, paradoxically, a high density of EBV-positive TILs in tumors is associated with inferior prognostic outcomes. Patients with HCC-IS could be candidates for immunotherapy. LAY SUMMARY: Hepatocellular carcinomas with histologic evidence of abundant immune cell infiltration are characterized by frequent activation of Epstein-Barr virus in tumor-infiltrating lymphocytes and less aggressive clinical behavior. However, a high density of Epstein-Barr virus-positive tumor-infiltrating lymphocytes is associated with inferior prognostic outcomes, possibly as a result of immune escape due to significant CD8 T cell exhaustion.
BACKGROUND & AIMS: The immunogenomic characteristics of hepatocellular carcinomas (HCCs) with immune cell stroma (HCC-IS), defined histologically, have not been clarified. We investigated the clinical and molecular features of HCC-IS and the prognostic impact of Epstein-Barr virus (EBV) infection. METHODS: We evaluated 219 patients with conventional HCC (C-HCC) and 47 with HCC-IS using in situ hybridization for EBV, immunohistochemistry, multiplex immunofluorescence staining, and whole exome and transcriptome sequencing. Human leukocyte antigen types were also extracted from the sequencing data. Genomic and prognostic parameters were compared between HCC-IS and C-HCC. RESULTS: CD8 T cell infiltration was more frequent in HCC-IS than C-HCC (mean fraction/sample, 22.6% vs. 8.9%, false discovery rate q <0.001), as was EBV positivity in CD20-positive tumor-infiltrating lymphocytes (TILs) (74.5% vs. 4.6%, p <0.001). CTNNB1 mutations were not identified in any HCC-IS, while they were present in 24.1% of C-HCC (p = 0.016). Inhibitory and stimulatory immune modulators were expressed at similar levels in HCC-IS and EBV-positive C-HCC. Global hypermethylation, and expression of PD-1 and PD-L1 in TILs, and PD-L1 in tumors, were also associated with HCC-IS (p <0.001), whereas human leukocyte antigen type did not differ according to HCC type or EBV positivity. HCC-IS was an independent factor for favorable recurrence-free survival (adjusted hazard ratio [aHR] 0.23; p = 0.002). However, a subgroup of tumors with a high density of EBV-positive TILs had poorer recurrence-free (aHR 25.48; p <0.001) and overall (aHR 9.6; p = 0.003) survival, and significant enrichment of CD8 T cell exhaustion signatures (q = 0.0296). CONCLUSIONS: HCC-IS is a distinct HCC subtype associated with a good prognosis and frequent EBV-positive TILs. However, paradoxically, a high density of EBV-positive TILs in tumors is associated with inferior prognostic outcomes. Patients with HCC-IS could be candidates for immunotherapy. LAY SUMMARY:Hepatocellular carcinomas with histologic evidence of abundant immune cell infiltration are characterized by frequent activation of Epstein-Barr virus in tumor-infiltrating lymphocytes and less aggressive clinical behavior. However, a high density of Epstein-Barr virus-positive tumor-infiltrating lymphocytes is associated with inferior prognostic outcomes, possibly as a result of immune escape due to significant CD8 T cell exhaustion.