Use of BUBR1 as a biomarker for predicting the response to a compound, preferably resistance of a disease such as cancer in a subject, wherein the compound is a compound of general formula I wherein R represents phenyl, thienyl or pyridinyl wherein phenyl is optionally substituted by one or two substituents independently selected from alkyl, halo-lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, acyloxy-lower alkyl, phenyl, hydroxy, lower alkoxy, hydroxy-lower alkoxy, lower alkoxy-lower alkoxy, phenyl-lower alkoxy, lower alkylcarbonyloxy, amino, monoalkylamino, dialkylamino, lower alkoxycarbonylamino, lower alkylcarbonylamino, substituted amino wherein the two substituents on nitrogen form together with the nitrogen heterocyclyl, lower alkylcarbonyl, carboxy, lower alkoxycarbonyl, cyano, halogen, and nitro; and wherein two adjacent substituents are methylenedioxy; and wherein pyridinyl is optionally substituted by lower alkoxy, amino or halogen; X represents a group C═Y, wherein Y stands for oxygen or nitrogen substituted by hydroxy or lower alkoxy; R1 represents hydrogen, lower alkylcarbonyl, hydroxy-lower alkyl or cyano-lower alkyl; R2, R3 and R6 represent hydrogen; R4 and R5, independently of each other, represent hydrogen, lower alkyl or lower alkoxy; or R4 and R5 together represent methylenedioxy; and pharmaceutically acceptable derivatives thereof; or wherein R represents phenyl or pyridinyl wherein phenyl is optionally substituted by one or two substituents independently selected from alkyl, halo-lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, acyloxy-lower alkyl, phenyl, hydroxy, lower alkoxy, hydroxy-lower alkoxy, lower alkoxy-lower alkoxy, phenyl-lower alkoxy, lower alkylcarbonyloxy, amino, monoalkylamino, dialkylamino, lower alkoxycarbonylamino, lower alkylcarbonylamino, substituted amino wherein the two substituents on nitrogen form together with the nitrogen heterocyclyl, lower alkylcarbonyl, carboxy, lower alkoxycarbonyl, formyl, cyano, halogen, and nitro; and wherein two adjacent substituents are methylenedioxy; and wherein pyridinyl is optionally substituted by lower alkoxy, amino or halogen; X represents oxygen; R1 represents hydrogen, lower alkylcarbonyl, hydroxy-lower alkyl or cyano-lower alkyl; R2, R3 and R6 represent hydrogen; R4 and R5, independently of each other, represent hydrogen, lower alkyl or lower alkoxy; or R4 and R5 together represent methylenedioxy; and pharmaceutically acceptable derivatives thereof. Methods of treatment of neoplastic and autoimmune diseases with these compounds are also disclosed.