Additionally, we determined H1‐0 expression in nine BCP‐ALL PDX samples by RT‐qPCR (n = 2 ETV6::RUNX1+, n = 4 high‐hyperdiploid, n = 2 BCR::ABL1+, n = 1 TCF3::PBX1+). The gene discussed is PBX1; the disease is acute lymphoblastic leukemia.