The study aimed to develop an animal model for prostate cancer by generating transgenic mice using the prostate-specific rat probasin (rPB) promoter to drive expression of the simian virus 40 large tumor antigen (SV40 Tag). High levels of transgene expression in the prostate led to progressive forms of prostatic disease, ranging from mild intraepithelial hyperplasia to large multinodular malignant neoplasia. Tumors were detected as early as 10 weeks of age and displayed characteristics similar to human prostate cancer, including elevated nuclear p53 levels and decreased androgen receptor expression. The establishment of breeding lines of transgenic mice that reproducibly develop prostate cancer provides a valuable tool for studying the molecular basis of transformation and progression to metastatic prostate cancer.The study aimed to develop an animal model for prostate cancer by generating transgenic mice using the prostate-specific rat probasin (rPB) promoter to drive expression of the simian virus 40 large tumor antigen (SV40 Tag). High levels of transgene expression in the prostate led to progressive forms of prostatic disease, ranging from mild intraepithelial hyperplasia to large multinodular malignant neoplasia. Tumors were detected as early as 10 weeks of age and displayed characteristics similar to human prostate cancer, including elevated nuclear p53 levels and decreased androgen receptor expression. The establishment of breeding lines of transgenic mice that reproducibly develop prostate cancer provides a valuable tool for studying the molecular basis of transformation and progression to metastatic prostate cancer.