P53 Mutation May Help Determine Prognosis for Bladder Cancer
According to a recent article in The Journal of Urology, the presence of p53 mutations may help indicate the prognosis for patients with bladder cancer.
The bladder is a hollow organ in the lower abdomen that stores urine. Transitional cell carcinoma, the most common type of bladder cancer, refers to bladder cancer involving the cells that line the inside of the bladder. Treatment of bladder cancer depends on the stage, or extent of disease, and may consist of the surgical removal of the bladder (radical cystectomy), surgical removal of the cancer tissue (transurethral resection) with preservation of the bladder, chemotherapy, radiation and/or biological therapy (treatment utilizing the immune system to fight cancer).
One gene, called the p53 gene, is of major focus in the evaluation of gene therapy, as a significant fraction of cancers have been shown to have a mutation (alteration) of this gene. The p53 gene, sometimes called the “cell suicide” gene, helps to keep normal cell replication under strict control. If there is a mutation in a cell’s DNA, or if a cell is infected with a virus, one action of the p53 gene is to stop further replication of this damaged cell, inhibiting further progression of the mutation. This occurs by stopping the growth of the cell or causing the cell to commit suicide (apoptosis). In cells that have a mutation within their p53 gene, there is no restraint on replication, leading to uncontrolled, rapid growth of the cell – the hallmark trait of cancer.
Previous clinical studies have indicated that there is a high rate of error in the initial determination of extent and/or aggressiveness (stage) of bladder cancer, which leads to suboptimal therapeutic approaches for these patients. Therefore, researchers are evaluating different “markers” that may aid in the correct initial staging diagnosis for bladder cancer, such as mutations within the p53 gene.
Researchers from Spain recently conducted a clinical study evaluating the association between mutations in the p53 gene to extent or aggressiveness of bladder cancer. This study involved 115 individuals who were divided into four groups: the first group (control group) did not have cancer; the second group had early-stage bladder cancer that had not spread from the outermost tissues (superficial) of the bladder; the third group had recurrent superficial bladder cancer; and the fourth group had bladder cancer that had spread from its site of origin. Patients had tissue samples from their bladder (control group) or cancer removed and examined through laboratory processes.
Mutations within the p53 gene were only found in patients with diagnosed bladder cancer; none were found in the control group. The presence of p53 mutations was 2.5 times higher in patients with cancer that had spread than in patients with superficial cancer. In addition, the presence of p53 mutations was over 4 times higher in patients with cancer cells that were considered aggressive in nature, compared to patients with less aggressive cancer.
These researchers concluded that the presence of a p53 mutation may aid in appropriate initial staging and subsequent treatment for patients diagnosed with bladder cancer. Patients with bladder cancer may wish to speak with their physician about the risks and benefits of p53 testing or the participation in a clinical trial further evaluating the p53 marker or other diagnostic approaches. Sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov).
Reference: Lorenzo-Romero J, Salinas-Sanchez A, Gimenez-Bachs F, et al. Prognostic implications of p53 gene mutations in bladder tumors.
The Journal of Urology. 2003;169:492-499.