Bladder cancer is one of the commoner malignancies in humans and current treatments for invasive disease typically give a five year survival rate of around fifty percent. Current chemotherapeutic agents increase survival by a small amount; clearly there is the need for improved treatments and for this, novel targets need to be identified. One putative target is the Fos family member Fos-related antigen-1 (Fra-1), which form part of the AP-1 transcription factor complex. Fra-1 is elevated in numerous human malignancies and regulates the transcription of genes involved in many aspects of the malignant process, such as migration and invasion. Regulatory control of Fra-1 has been incompletely studied to date; it is known that MAP Kinase dependent signalling can influence Fra-1 accumulation but other aspects of control are only now being elucidated. This thesis demonstrates that Fra-1 is present in the majority of bladder cancers, that it is regulated by the structure of the C-terminus and MAP Kinase dependent phosphorylation of the amino acids Ser[superscript 252] and Ser[superscript 265], and undergoes proteasomal degradation. This highlights the potential role of Fra-1 as a novel therapeutic target and provides more information on the regulation of Fra-1 which may be targeted with novel agents.