This invention relates to the treatment of conditions, such as cancer, associated with 5-lipoxygenase (5-LO) expression using ?lapachone compounds that inhibit 5-lipoxygenase (5-LO), such as ? lapachone and derivatives thereof. Methods of treatment of conditions associated with 5-lipoxygenase (5-LO) expression as well as medical uses of ?lapachone compounds in such methods are provided, as well as methods of selecting or prognosing cancer patients.