Many genetic alterations have recently been identified in transitional cell
carcinoma (TCC) of the bladder. These include alterations to known proto-o
ncogenes and tumour suppressor genes and the identification of multiple sit
es of nonrandom chromosomal deletion which are predicted to define the loca
tion of as yet unidentified tumour suppressor genes. This review summarises
recent efforts to define the location of novel bladder tumour suppressor g
enes using loss of heterozygositiy (LOH) and homozygous deletion analyses a
nd to isolate the genes targeted by these deletions. For three of the four
regions of deletion on chromosome 9, the most frequently deleted chromosome
in TCC, candidate genes have been identified. It is anticipated that the i
dentification of the genes and/or genetic regions which are frequently alte
red in TCC will provide useful tools for diagnosis, prediction of prognosis
, patient monitoring and novel therapies.