Interestingly, loss of atrx was found to cooperate with p53 deficiency in promoting the development of sarcomas in zebrafish (Oppel et al., 2019), and in our cohort, 3/4 (75%) canine HSAs with ATRX mutations also had TP53 mutations (Fig. 4; Fig. S2). The gene discussed is TP53; the disease is sarcoma.