Biologic factors affect the ability of radiation to effectively treat all patients with prostate cancer. The use of prognostic and genetic markers (12 lipoxygenase, p53, bc1-2 genes, ploidy) may aid in the development of treatments for these patients. Particularly, several studies have shown that p53 tumor suppressor gene mutations are infrequent in prostate cancer and are associated with advanced disease. Recent efforts have been directed toward novel therapeutic modalities, especially in combination with standard irradiation of prostate carcinoma. These modalities are based on an improved knowledge of these biological factors involved in the progression and diffusion of the tumor, especially p53. Several authors evaluated the predictive and prognostic role of p53 in patients with prostatic cancer treated with radiotherapy. An extensive review of international reports on the subject is provided.