The present invention relates to a method of treating a warm-blooded animal, especially a human subject, having leukaemia, preferably acute myeloid leukemia (AML), B and T acute lymphoblastic leukemias (B-ALL and T-ALL), or chronic myeloid leukemia (CML), or a lymphoma or a solid tumour, comprising administering to said animal a therapeutically effective amount of a compound having any of the formulae identified throughout the present specification, optionally together or in combination with a conventional compound or compound mixture useful in any of said treatments, in particular a topoisomerase II inhibitor, an antimetabolite, or an antitumor antibiotic, and optionally at least one pharmaceutically acceptable carrier, for simultaneous, separate or sequential use; and to a pharmaceutical composition and a commercial package comprising said compound.