The 2016 American Society for Transplantation and Cellular Therapy (ASTCT) guidelines recommend allogeneic HCT for eligible patients with relapsed standard-risk CLL who develop BTK inhibitor resistance, and for high-risk patients with deletion 17p, TP53 aberrations, and/or complex karyotype who have relapsed after 2 lines of therapy and/or a BTK or BCL2 inhibitor (2). The gene discussed is TP53; the disease is B-cell chronic lymphocytic leukemia.