TCR-Seq Identifies Distinct Repertoires of Distant-Metastatic and Nondistant-Metastatic Thyroid Tumors.

Abstract

Malignant thyroid tumor with distant metastasis is associated with poor outcome. Early detection of distant metastasis is of great clinical importance. Thyroid tumor infiltrated with T cells can serve as a biomarker for monitoring metastasis. A retrospective analysis was performed of patient clinical samples collected between 2012 to 2018, using T-cell receptor sequencing (TCR-seq) for clinical exploration. This study took place at Zhejiang Cancer Hospital. Sixty-eight patients with papillary thyroid cancer (PTC) (distinct metastatic status) and 21 patients with benign nodules were enrolled. All patients had not received any treatment before surgery. The characteristics of TCRβ complementary-determining region 3 (CDR3) for each patient were determined by high-throughput sequencing. The TCRβ diversity of malignant tumors is significantly higher than benign nodules both in blood and tumor samples (Shannon index, blood, P < .01; tumor, P < .001). The malignant tumors with distant metastasis or invasiveness showed lower TCRβ diversity than nonmetastasis (Shannon index, P < .01) or noninvasive (Shannon index, P < .01) malignant tumors. Analysis of the Morisita-Horn similarity index indicated significant TCRβ repertoire similarity between tumor and blood in distant-metastatic patients (comparison with nonmetastasis, P < .05). According to the discrepancy of the CDR3 among patients with different clinicopathological status, the classifier was constructed to discriminate distant-metastatic individuals. A promising area under the curve value of 83.8% was obtained with the number of overlapping CDR3 clonotypes. The availability and reliability of TCR-seq render it prospective to translate these intrinsic attributes into clinical practice for monitoring distant metastasis in PTC patients.