NKX2-2 and Ewing sarcoma: Therefore, it will be worth to explore whether our finding that NKX2–1 positive cancers are sensitive to sertraline and etoposide can be extended to cancer types that overexpress other NKL homeobox genes such as NKX2-2 in Ewing’s sarcoma [54], NKX2-5 in ovarian yolk sac tumours [55] and NKX3-1 in prostate cancer and ductal/lobular breast carcinomas [56].