Abstract: Disclosed is a method for selecting a potential subject with benefiting from a pharmaceutical composition for treating or preventing cancer, comprising: determining the presence or absence of a mutation in tumor protein p53 (TP53) gene and/or BCL6 co-repressor (BCOR) gene by using a sample collected from the subject; and providing an indication that the subject is a potential subject with benefiting from the pharmaceutical composition in the case of TP53 wild type and/or BCOR wild type.

Abstract: The present invention provides an anti-tumor agent comprising a compound of formula (1) or a pharmaceutically acceptable salt thereof, wherein ring Q1 is optionally-substituted C6-10 aryl, etc.; R1 and R2 are independently hydrogen atom, etc.; W1 is C1-4 alkylene which may be optionally substituted with 1 to 3 fluorine atoms or C3-7 cycloalkyl; W2 is —NR4aC(O)—, etc. wherein R4a is hydrogen atom or C1-6 alkyl; ring Q2 is optionally-substituted C6-10 aryl, etc., in combination with at least one agent selected from the group consisting of an anti-cancer agent, an anti-diabetic agent, an agent for treating dyslipidemia, an agent for treating multiple sclerosis, a steroidal anti-inflammatory agent, a non-steroidal anti-inflammatory agent, an anti-fungal agent, and a pharmaceutically acceptable salt thereof.