The present invention relates to the combination of a BRD4 inhibitor with an antifolate (particularly an MTHFD1 inhibitor) for use in the treatment or prevention of cancer. The invention also relates to an antifolate (particularly an MTHFD1 inhibitor) for use in resensitizing a BRD4 inhibitor-resistant cancer to the treatment with a BRD4 inhibitor. The invention further provides a pharmaceutical composition comprising a BRD4 inhibitor, an antifolate (particularly an MTHFD1 inhibitor), and a pharmaceutically acceptable excipient. Moreover, the invention provides a method of assessing the susceptibility or responsiveness of a subject to the treatment with a BRD4 inhibitor, wherein the subject has been diagnosed as suffering from cancer or is suspected of suffering from cancer, the method comprising determining the level of nuclear folate and/or the level of expression of MTHFD1 in a sample obtained from the subject.
