Supplementary Fig. S1: Stepwise accumulation of segmental chromosomal aberrations (SCAs) in chromosome 7 of the case study. Supplementary Fig. S2: Whole genome views of 10 different samples of a single stage 4 neuroblastoma patient. Supplementary Fig: S3: Allele difference tracks and smooth signals of chromosome 1q of four different samples of the case study. Supplementary Fig. S4: I-FISH for visualization of 1q deletion in the DTCs at diagnosis and tumor 6 at diagnosis. Supplementary Fig. S5: Frequencies of common segmental chromosomal aberrations in the DTCs with and without 1q deletions at diagnosis and relapse. Supplementary Fig. S6: Deleted regions of 19q in different patients. Supplementary Fig. S7: Event-free and overall survival curves for patients with and without 1q, 19q, or ATRX deletions in the primary tumors. Supplementary Fig. S8: Event-free and overall survival curves for patients with and without 1q, 19q, or ATRX deletions in the diagnostic DTCs.
ARTICLE ABSTRACT
Purpose: Tumor relapse is the most frequent cause of death in stage 4 neuroblastomas. Since genomic information on the relapse precursor cells could guide targeted therapy, our aim was to find the most appropriate tissue for identifying relapse-seeding clones.Experimental design: We analyzed 10 geographically and temporally separated samples of a single patient by SNP array and validated the data in 154 stage 4 patients.Results: In the case study, aberrations unique to certain tissues and time points were evident besides concordant aberrations shared by all samples. Diagnostic bone marrow–derived disseminated tumor cells (DTCs) as well as the metastatic tumor and DTCs at relapse displayed a 1q deletion, not detected in any of the seven primary tumor samples. In the validation cohort, the frequency of 1q deletion was 17.8%, 10%, and 27.5% in the diagnostic DTCs, diagnostic tumors, and DTCs at relapse, respectively. This aberration was significantly associated with 19q and ATRX deletions. We observed a significant increased likelihood of an adverse event in the presence of 19q deletion in the diagnostic DTCs.Conclusions: Different frequencies of 1q and 19q deletions in the primary tumors as compared with DTCs, their relatively high frequency at relapse, and their effect on event-free survival (19q deletion) indicate the relevance of analyzing diagnostic DTCs. Our data support the hypothesis of a branched clonal evolution and a parallel progression of primary and metastatic tumor cells. Therefore, searching for biomarkers to identify the relapse-seeding clone should involve diagnostic DTCs alongside the tumor tissue. Clin Cancer Res; 23(15); 4224–32. ©2017 AACR.
