Uncertain Whether P53 Predicts Bladder Cancer Prognosis
In spite of a decade of research, a review published in The Lancet Oncology concludes that it is still not clear whether levels of the protein P53 can be used to predict recurrence, progression, and survival of patients with bladder cancer.
The bladder is an organ in the lower abdomen that stores urine after it is released from the kidneys until it is passed out of the body. Bladder cancer is the fifth most common type of cancer in the United States and causes approximately 13,000 deaths annually. Bladder cancer occurs predominantly in elderly men and less frequently in women and younger men.
Prognosis for bladder cancer varies greatly. Researchers have tried to identify characteristics of the cancer that will help predict which patients are most at risk for recurrence and progression. A characteristic that has received a great deal of research attention is the level of the protein P53. P53 plays a role in several aspects of cell growth and survival, and mutations in the gene that produce this protein have been found in many cancers. High levels of the P53 protein suggest that there may a gene mutation.
In order to determine whether levels of P53 in bladder cancer can be used to predict cancer recurrence, progression, and survival, researchers in Spain reviewed clinical studies of bladder cancer and P53 published between 1993 and 2003. Conclusions were drawn from a subset of studies that had a similar design, enabling them to be combined in a single analysis. In these studies, researchers found that high levels of P53 were weakly associated with an increased risk of recurrence, progression, and death. The researchers caution, however, that these analyses were based on only a few studies.
The researchers conclude that although there is some evidence that P53 levels are associated with bladder cancer prognosis, the evidence is not strong enough to guide the medical management of bladder cancer patients. Before P53 can be used (or rejected) as a marker for poor-prognosis bladder cancer, results from larger studies with more consistent laboratory methods are needed.
Reference: Malats N, Bustos A, Nascimento CM et al. P53 as a prognostic marker for bladder cancer: a meta-analysis and review. The Lancet Oncology. 2005;6:678-686.