TRBV and TRBJ usage, when paired with specific HLA alleles, associates with distinct head and neck cancer survival rates

TCR gene segment usage and HLA alleles that are associated with cancer survival rates also represent racial disparities

Understanding racial disparities in cancer outcomes continues to be a challenge, with likely many factors at play, including socioeconomic factors and genetic polymorphisms impacting basic cellular and molecular functions. Additionally, it is possible that specific combinations of environment and genetics have specific impacts. T-cell receptor (TCR) gene segment usage, HLA allele combinations have been associated with autoimmune and infectious disease courses, and more recently, TCR gene segment usage, HLA allele combinations have been associated with distinct survival outcomes in cancer as well. We examined several such, previously reported cancer-related TCR gene segment usage, HLA allele combinations for evidence of racial disparities, with regard to the prevalence of the combination in different racial groups. Results indicated that TCR gene segment usage, potentially reflecting environmental factors related to previous pathogen exposure, in combination with certain HLA alleles or independently, may represent a novel explanation for racial disparities in cancer outcomes. Overall, at this point, a genetic connection to racial disparities in cancer outcomes is detectable but remains modest, suggesting that other factors, such as socioeconomic factors, remain as important considerations.

Archaic humans have contributed to large-scale variation in modern human T cell receptor genes

Human T cell receptors (TCRs) are critical for mediating immune responses to pathogens and tumors and regulating self-antigen recognition. Yet, variations in the genes encoding TCRs remain insufficiently defined. Detailed analysis of expressed TCR alpha, beta, gamma, and delta genes in 45 donors from four human populations-African, East Asian, South Asian, and European-revealed 175 additional TCR variable and junctional alleles. Most of these contained coding changes and were present at widely differing frequencies in the populations, a finding confirmed using DNA samples from the 1000 Genomes Project. Importantly, we identified three Neanderthal-derived, introgressed TCR regions including a highly divergent TRGV4 variant, which mediated altered butyrophilin-like molecule 3 (BTNL3) ligand reactivity and was frequent in all modern Eurasian population groups. Our results demonstrate remarkable variation in TCR genes in both individuals and populations, providing a strong incentive for including allelic variation in studies of TCR function in human biology.

Specific TCR V-J gene segment recombinations leading to the identification pan-V-J CDR3s associated with survival distinctions: diffuse large B-cell lymphoma

In the diffuse large B-cell lymphoma (DLBCL) setting, we examined lymph node biopsy, T-cell receptor features, and the DLBLC patient human leukocyte antigen (HLA) alleles, to provide a basis for assessing survival distinctions represented by the National Cancer Institute Center for Cancer Research (NCICCR) dataset. While previous analyses of other cancer datasets have indicated that specific T-cell receptor (TCR) V or J gene segments, independently, can be associated with a survival distinction, we have here identified V-J recombinations, representing specific V and J gene segments associated with survival distinctions. As specific V-J recombinations represent relatively conserved complementarity determining region-3 (CDR3) amino acid sequences, we assessed the entire DLBCL NCICCR dataset for such conserved CDR3 features. Overall, this approach indicated the opportunity of identifying DLBCL patient subpopulations with TCR CDR3 features, and HLA alleles, with significant survival distinctions, possibly identifying cohorts more likely to benefit from a given immunotherapy.