While the exact role of each miRNA in Cluster 4, 1 and 3 is yet to be defined, it is noteworthy that miR-145, which has been implicated as an inhibitor of cell proliferation by down-regulating IGF1R in bladder cancer cells [44] and other cancers [45–47], was present in Cluster 4. This evidence concerns the gene IGF1R and urinary bladder cancer.