BCR and neoplasm: We observed a significant reduction in B cell receptor clonotype diversity in the emerging lcl_burn0214 cell line relative to the parental tumor, with the proportion of the most frequent BCR clonotype reaching 92–99%, compared to 10–28% in the original tumor tissue specimen tum_burn0214, indicating the near monoclonal nature of the lcl_burn0214 cell line (Fig. 1D, Supplementary Table 1).