Heterogeneous immunogenomic features and distinct escape mechanisms in multifocal hepatocellular carcinoma.

BACKGROUND & AIMS: The presence of multifocal tumors, developed either from intrahepatic metastasis (IM) or multicentric occurrence (MO), is a distinct feature of hepatocellular carcinoma (HCC). Immunogenomic characterization of multifocal HCC is important for understanding immune escape in different lesions and developing immunotherapy. METHODS: We combined whole-exome/transcriptome sequencing, multiplex immunostaining, immunopeptidomes, T cell receptor (TCR) sequencing and bioinformatic analyses of 47 tumors from 15 patients with HCC and multifocal lesions. RESULTS: IM and MO demonstrated distinct clonal architecture, mutational spectrum and genetic susceptibility. The immune microenvironment also displayed spatiotemporal heterogeneity, such as less T cell and more M2 macrophage infiltration in IM and higher expression of inhibitory immune checkpoints in MO. Similar to mutational profiles, shared neoantigens and TCR repertoires among tumors from the same patients were abundant in IM but scarce in MO. Combining neoantigen prediction and immunopeptidomes identified T cell-specific neoepitopes and achieved a high verification rate in vitro. Immunoediting mainly occurred in MO but not IM, due to the relatively low immune infiltration. Loss of heterozygosity of human leukocyte antigen (HLA) alleles, identified in 17% of multifocal HCC, hampered the ability of major histocompatibility complex to present neoantigens, especially in IM. An integrated analysis of Immunoscore, immunoediting, TCR clonality and HLA loss of heterozygosity in each tumor could stratify patients into 2 groups based on whether they have a high or low risk of recurrence (p = 0.038). CONCLUSION: Our study comprehensively characterized the genetic structure, neoepitope landscape, T cell profile and immunoediting status that collectively shape tumor evolution and could be used to optimize personalized immunotherapies for multifocal HCC. LAY SUMMARY: Immunogenomic features of multifocal hepatocellular carcinoma (HCC) are important for understanding immune-escape mechanisms and developing more effective immunotherapy. Herein, comprehensive immunogenomic characterization showed that diverse genomic structures within multifocal HCC would leave footprints on the immune landscape. Only a few tumors were under the control of immunosurveillance, while others evaded the immune system through multiple mechanisms that led to poor prognosis. Our study revealed heterogeneous immunogenomic landscapes and immune-constrained tumor evolution, the understanding of which could be used to optimize personalized immunotherapies for multifocal HCC.

Programmed death-ligand 1 (PD-L1)/thyroid transcription factor-1 double immunohistochemical staining facilitates scoring of tumor PD-L1 expression in cytopathology specimens from lung adenocarcinoma patients.

BACKGROUND: Immune checkpoint inhibitor therapy has revolutionized lung adenocarcinoma therapy. Treatment with antibodies against the immune checkpoint molecules programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) can induce a durable response in a subset of patients. Immunohistochemistry characterization of tumor PD-L1 expression using either a histopathology specimen or a cytopathology specimen has been shown to correlate with treatment response. However, the current practice relies on pathologists' visual estimation of tumor PD-L1 staining, which can be variable in certain conditions. Highlighting tumor cells via double immunostaining with PD-L1 and thyroid transcription factor-1 (TTF-1) may improve estimation accuracy. METHODS: We performed PD-L1 single staining and PD-L1/TTF-1 double staining in 42 pairs of cytopathology and histopathology specimens from lung adenocarcinoma patients. An experienced pathologist visually estimated PD-L1 expression in each case and placed tumor PD-L1 expression into 1 of 3 categories: <1%, 1%-49%, or ≥50%. A medical technologist also performed estimations of the same cases based on a count of 200 tumor cells, and the results were compared. RESULTS: PD-L1/TTF-1 double immunohistochemistry could better identify the PD-L1-positive tumor cells in cytopathology specimens compared with PD-L1 single staining. The concordance of PD-L1 expression categorization between the pathologist's visual estimation and the medical technologist's counting was increased by double staining in cytopathology specimens (Cohen's weighted kappa: single stain, 0.784; double stain, 0.880). Double staining reduced possible error in the pathologist's visual estimation of PD-L1 expression from 9.5% to 4.8%. The benefit was not observed in histopathology specimens. CONCLUSION: A simple PD-L1/TTF-1 double immunohistochemistry technique can be applied successfully to cytopathology specimens in better identifying patients who can potentially benefit from immune checkpoint blockade treatment.

Anal human papillomavirus and its associations with abnormal anal cytology among men who have sex with men.

Human papillomavirus (HPV) infection contributes to most anal cancers and premalignant intraepithelial lesions. This study investigated anal HPV infections and cytological abnormalities among men who have sex with men (MSM). Sociodemographic characteristics and sexual behaviors were collected by using a structured questionnaire. Anal cytological results were examined, and HPV genotyping was performed by the Linear Array HPV Genotyping test. Logistic regression was used to estimate risk factors and their associations with high-risk HPV infection and cytological abnormalities. Among 163 MSM, 101 were seropositive for human immunodeficiency virus (HIV) and 62 were seronegative for HIV. The overall prevalence of HPV was 66.2%. A total of 61.9% and 48.2% of participants had never acquired any of either the quadrivalent or nonavalent vaccine HPV types, respectively. Cytological findings showed 15.3% atypical squamous cells of undetermined significance, 16.6% low-grade squamous intraepithelial lesion, 4.9% atypical squamous cells that cannot exclude high-grade squamous intraepithelial lesion and 17% high-grade squamous intraepithelial lesion. The number of high-risk HPV types was the predominant risk factor for abnormal anal cytology (OR 2.02, 95% CI 1.27-3.24). Infection with high-risk HPV was a significant predictor for cytological abnormality. MSM should be encouraged to obtain the HPV vaccine.