The present invention relates to a method for diagnosing the risk of cancer recurrence in a mammalian patient, comprising detecting the expression of macroH2A1.1 and/or macroH2A2 in a biological sample obtained from said patient, wherein a low or reduced expression of said macroH2A1.1 and/or macroH2A2 is indicative for an increased risk of cancer recurrence in said patient. The present invention is further directed at improved methods for treating cancer, in particular breast and/or lung cancer, based on said diagnostic method.
