characterization of t cell repertoire of blood, tumor, and ascites in ovarian cancer patients using next generation sequencing
tumor-infiltrating lymphocytes (tils) play an important role in regulating the host immune response and are one of key factors in defining tumor microenvironment. some studies have indicated that t cell infiltration in malignant ascites is associated with clinical outcome, but few studies have performed detailed characterization of t cell diversity or clonality in malignant effusions. we have applied a next generation sequencing method to characterize t cell repertoire of a set of primary cancers, ascites, and blood from 12 ovarian cancer patients and also analyzed the t cell subtype populations in malignant fluids from 3 ovarian cancer patients. we observed enrichment of certain t cells in tumors and ascites, but most of the enriched t cell receptor (tcr) sequences in tumors and ascites were not common. moreover, we analyzed tcr sequences of t cell subtypes (cd4 , cd8 , and regulatory t cells) isolated from malignant effusions and also found clonal expansion of certain t cell populations, but the tcr sequences were almost mutually exclusive among the three subgroups. although functional studies of clonally expanded t cell populations are definitely required, our approach offers a detailed characterization of t cell immune microenvironment in tumors and ascites that might differently affect antitumor immune response.