This invention relates to methods for determining the presence of cancer in a subject based on the analysis of the expression levels of an under-expressed tumour marker (TM) and at least one other TM. Specifically, this invention relates to the determination of a cancer, particularly bladder cancer, by performing ratio, regression or classification analysis of the expression levels of at least one under-expressed TM, particularly an under-expressed bladder TM (BTM), and at least one over-expressed TM, particularly an over-expressed BTM. In various aspects, the invention telates to kits and devices for carrying out these methods.