TERT and neoplasm: Interestingly, patient NB67R5, with two different TERT-associated structural variants in primary and relapsed tumors, also had two mutations in the chromatin-associated genes ARID1A and ARID1B. The primary tumor of NB67R5 had a structural variant causing disruption of ARID1B, a variant that was lost in the relapse sample, which instead carried a missense mutation in ARID1A (Fig. 1D, and Supplemental Tables 2 and 3).