Kim HD, et al. - For this investigation, researchers obtained hepatocellular carcinoma (HCC) specimens, along with adjacent non-tumor tissues and blood samples, from 90 patients who had a surgical resection at Asan Medical Center (in Seoul, Korea) from April 2016 through April 2018 to examine features of exhaustion in CD8⁺ T cells isolated from HCC specimens. They observed HCC specimens to contain CD8⁺ T cells that express different levels of programmed cell death 1 (PDCD1 or PD1). It was noted that HCCs with high proportions of PD1-high CD8⁺ T cells express TIM3 and/or lymphocyte activating 3 (LAG3) and produce low levels of interferon gamma (IFNG) and tumor necrosis factor (TNF) in response to anti-CD3. Findings revealed that incubation of these cells with antibodies against PD1 and TIM3 or LAG3 further restore proliferation and production of cytokines. Results of this study suggested that HCCs with high proportions of PD1-high CD8⁺ T cells might be more susceptible to combined immune checkpoint blockade-based therapies.