Association of p53 Mutations with Metastatic Prostate Cancer
Tumor Suppressor Protein p53
In prostate cancer, mutation of the p53 tumor suppressor gene has been associated with locally advanced disease and hormone-resistant disease that is predominantly localized to bone. However, little is known regarding the status of the p53 gene in metastatic prostate cancer that has not been treated with hormonal manipulation. We evaluated formalin-fixed, paraffin-embedded malignant tissues from 86 patients with various stages of prostate cancer, including pathologically confined, locally advanced, and metastatic disease, to detect abnormal p53 nuclear protein accumulation using immunohistochemistry. No abnormal p53 immunostaining was detected in 18 patients with prostate cancer confined to the gland. Two tumors from 21 patients with locally advanced disease (extracapsular extension and/or seminal vesicle invasion) had abnormal nuclear p53 accumulation, and a mutation in exon 7 of the p53 gene was detected in tumor DNA from one patient using single-strand conformation polymorphism-direct sequencing analysis. Of the remaining 47 patients studied in whom tissues from the prostate gland and a metastatic site (44 lymph node, 2 bone, and 1 lung) were available, only 3 had received hormonal therapy prior to obtaining metastatic tissue. In four patients both primary and metastatic tumors demonstrated accumulation of p53 protein, whereas seven additional patients exhibited p53 accumulation only at the metastatic site. In three patients the metastatic tumors harbored missense single-base substitutions in exon 5, as detected using single-strand conformation polymorphism-direct sequencing. These results indicate that p53 abnormalities are associated with lymph node metastases derived from prostate cancer patients that had not undergone hormonal therapy.