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Enrichment of CD103 + tumor-infiltrating T lymphocytes (TIL) is associated with improved outcomes in patients. However, the characteristics of human CD103 + cytotoxic CD8 + T cells (CTL) and their role in tumor control remain unclear. We investigated the features and antitumor mechanisms of CD103 + CTLs by assessing T-cell receptor (TCR)-matched CD103 + and CD103 - cancer-specific CTL immunity in vitro and its immunophenotype ex vivo Interestingly, we found that differentiated CD103 + cancer-specific CTLs expressed the active form of TGFβ1 to continually self-regulate CD103 expression, without relying on external TGFβ1-producing cells. The presence of CD103 on CTLs improved TCR antigen sensitivity, which enabled faster cancer recognition and rapid antitumor cytotoxicity. These CD103 + CTLs had elevated energetic potential and faster migration capacity. However, they had increased inhibitory receptor coexpression and elevated T-cell apoptosis following prolonged cancer exposure. Our data provide fundamental insights into the properties of matured human CD103 + cancer-specific CTLs, which could have important implications for future designs of tissue-localized cancer immunotherapy strategies., (©2019 American Association for Cancer Research.)

Purpose: Fresh-frozen (FF) tissue is the optimal source of DNA for whole-genome sequencing (WGS) of cancer patients. However, it is not always available, limiting the widespread application of WGS in clinical practice. We explored the viability of using formalin-fixed, paraffin-embedded (FFPE) tissues, available routinely for cancer patients, as a source of DNA for clinical WGS., Methods: We conducted a prospective study using DNAs from matched FF, FFPE, and peripheral blood germ-line specimens collected from 52 cancer patients (156 samples) following routine diagnostic protocols. We compared somatic variants detected in FFPE and matching FF samples., Results: We found the single-nucleotide variant agreement reached 71% across the genome and somatic copy-number alterations (CNAs) detection from FFPE samples was suboptimal (0.44 median correlation with FF) due to nonuniform coverage. CNA detection was improved significantly with lower reverse crosslinking temperature in FFPE DNA extraction (80 °C or 65 °C depending on the methods). Our final data showed somatic variant detection from FFPE for clinical decision making is possible. We detected 98% of clinically actionable variants (including 30/31 CNAs)., Conclusion: We present the first prospective WGS study of cancer patients using FFPE specimens collected in a routine clinical environment proving WGS can be applied in the clinic.