TY - JOUR T1 - Neoantigen load and HLA-class I expression identify a subgroup of tumors with a T-cell-inflamed phenotype and favorable prognosis in homologous recombination-proficient high-grade serous ovarian carcinoma JF - Journal for ImmunoTherapy of Cancer JO - J Immunother Cancer DO - 10.1136/jitc-2019-000375 VL - 8 IS - 1 SP - e000375 AU - Hirokazu Matsushita AU - Kosei Hasegawa AU - Katsutoshi Oda AU - Shogo Yamamoto AU - Kayo Asada AU - Takahiro Karasaki AU - Akira Yabuno AU - Akira Nishijima AU - Takahide Nejo AU - Yukari Kobayashi AU - Sho Sato AU - Yuji Ikeda AU - Manami Miyai AU - Yusuke Takahashi AU - Rui Yamaguchi AU - Keiichi Fujiwara AU - Hiroyuki Aburatani AU - Kazuhiro Kakimi Y1 - 2020/05/01 UR - http://jitc.bmj.com/content/8/1/e000375.abstract N2 - Background There is increasing evidence for the benefit of poly ADP ribose polymerase (PARP) inhibitors in a subset of high-grade serous ovarian carcinoma (HGSC) patients, especially those with homologous recombination (HR)-deficient tumors. However, new treatment strategies, such as immune checkpoint inhibition, are required for patients with HR-proficient tumors.Methods A total of 80 cases of HGSC were analyzed in this study. Whole exome and RNA sequencing was performed for these tumors. Methylation arrays were also carried out to examine BRCA1 and RAD51C promoter methylation status. Mutations, neoantigen load, antigen presentation machinery, and local immune profile were investigated, and the relationships of these factors with clinical outcome were also analyzed.Results As expected, the numbers of predicted neoAgs were lower in HR-proficient (n=46) than HR-deficient tumors (n=34). However, 40% of the patients with HR-proficient tumors still had higher than median numbers of neoAgs and better survival than patients with lower numbers of neoAgs. Incorporation of human leukocyte antigen (HLA)-class I expression status into the survival analysis revealed that patients with both high neoAg numbers and high HLA-class I expression (neoAghiHLAhi) had the best progression-free survival (PFS) in HR-proficient HGSC (p=0.0087). Gene set enrichment analysis demonstrated that the genes for effector memory CD8 T cells, TH1 T cells, the interferon-γ response, and other immune-related genes, were enriched in these patients. Interestingly, this subset of patients also had better PFS (p=0.0015) and a more T-cell-inflamed tumor phenotype than patients with the same phenotype (neoAghiHLAhi) in HR-deficient HGSC.Conclusions Our results suggest that immune checkpoint inhibitors might be an alternative to explore in HR-proficient cases which currently do not benefit from PARP inhibition. ER -