Characteristic examples are the decrease in EPHA2 expression after doxorubicin treatment in responding patients with neuroblastoma [97], the increased expression of EPHB1 in medulloblastoma radiosensitive tumors [101], the correlation of EPHB6 overexpression in T-ALL with sensitivity to doxorubicin [103], and the association of ephrin-A4 cytoplasmic expression in osteosarcoma and an inferior response to chemotherapy [71]. The gene discussed is EFNA4; the disease is osteosarcoma.