Novel fused pyrimidine compound or salt thereof

A method for treating a malignant tumor comprising administering a compound represented by Formula (I) below or a salt thereof to a mammal:

• wherein in Formula (I), A is
• wherein R1 is selected from the group consisting of
• halogen,
• cyano,
• nitro,
• substituted or unsubstituted C1-C6 alkyl,
• substituted or unsubstituted C1-C6 alkoxy,
• substituted or unsubstituted C2-C6 alkenyl,
• substituted or unsubstituted C2-C6 alkynyl,
• substituted or unsubstituted amino, and
• a substituted or unsubstituted 4- to 10-membered monocyclic or polycyclic unsaturated heterocyclic group containing 1 to 3 identical or different heteroatoms selected from nitrogen, oxygen, and sulfur,
• Y is N or CH, and
• n is an integer of 0 to 2,
• wherein when n is 2, the two R1 may be identical or different from each other;
• in Formula A2, the group:
• forms, together with phenyl or pyridinyl to which this group is bonded, polycyclic C8-C14 aromatic hydrocarbon or an 8- to 14-membered polycyclic unsaturated heterocyclic group containing 1 to 3 identical or different heteroatoms selected from nitrogen, oxygen, and sulfur;
• R2 is selected from the group consisting of
• substituted or unsubstituted C3-C10 alkyl,
• substituted or unsubstituted C3-C7 cycloalkyl,
• substituted or unsubstituted C4-C12 bridged cycloalkyl,
• substituted or unsubstituted C2-C6 alkenyl,
• substituted or unsubstituted C3-C7 cycloalkenyl, and
• a substituted or unsubstituted 4- to 10-membered monocyclic or polycyclic saturated heterocyclic group containing 1 to 3 identical or different heteroatoms selected from nitrogen, oxygen, and sulfur,
• provided that when each group represented by R2 has a substituent, the substituent must not be a substituted or unsubstituted saturated heterocyclic group that may have at least one identical or different heteroatom selected from oxygen and sulfur, and has
• at least one nitrogen atom;
• and
• X is
• N or
• CR3, wherein R3 is selected from the group consisting of
• hydrogen,
• halogen,
• cyano,
• nitro,
• substituted or unsubstituted C1-C6 alkyl,
• substituted or unsubstituted C1-C6 alkoxy,
• substituted or unsubstituted C1-C6 alkylthio,
• substituted or unsubstituted C3-C7 cycloalkyl,
• substituted or unsubstituted C2-C6 alkenyl,
• substituted or unsubstituted C2-C6 alkynyl,
• substituted or unsubstituted amino,
• substituted or unsubstituted carbamoyl,
• substituted or unsubstituted C6-C14 aromatic hydrocarbon, and
• a substituted or unsubstituted 4- to 10-membered monocyclic or polycyclic saturated or unsaturated heterocyclic group containing 1 to 3 identical or different heteroatoms selected from nitrogen, oxygen, and sulfur.