TERT and metastatic malignant neoplasm in the lymph nodes: The patient-specific TERT breakpoint ddPCR assay required at least 2 ng genomic tumor DNA (Supplementary Fig. S3B) and detected breakpoint copies (Fig. 1B) at initial biopsy (22.0 copies/ng DNA) and postchemotherapy surgical resection (42.8 copies/ng primary tumor DNA, 18.1 copies/ng local lymph node metastasis DNA), thus validating our experimental approach in patient biomaterial samples (Supplementary Table S5).