Association between changes due to training in baseline cardiorespiratory fitness (VO2peakpost–pre) and changes in baseline plasma BDNF or serum BDNF (pBDNFS4–S1 or sBDNFS4–S1, respectively) in the whole sample (ALL) and separately in groups CE, PE, CE + PE, and PE + CE. The gene discussed is BDNF; the disease is acute lymphoblastic leukemia.