Although ARNT amplification could be a proxy for chr1q amplification (and other genes in this region, such as SETDB1, might functionally contribute to prognostic differences), it is an interesting candidate for future investigation: it is the only COSMIC cancer gene within the amplified region, germline polymorphisms in ARNT are associated with an increased risk of bladder cancer [67], and the protein encoded by ARNT dimerises with the protein encoded by the AHR gene which is recurrently mutated in UBC [59]. Here, AHR is linked to urinary bladder cancer.