Establishment and genomic characterization of mouse xenografts of human primary prostate tumors.

Serum prostate-specific antigen screening has led to earlier detection and surgical treatment of prostate cancer, favoring an increasing incidence-to-mortality ratio. However, about one third of tumors that are diagnosed when still confined to the prostate can relapse within 10 years from the first treatment. The challenge is therefore to identify prognostic markers of aggressive versus indolent tumors. Although several preclinical models of advanced prostate tumors are available, a model that recapitulates the genetic and growth behavior of primary tumors is still lacking. Here, we report a complete histopathological and genomic characterization of xenografts derived from primary localized low- and high-grade human prostate tumors that were implanted under the renal capsule of immunodeficient mice. We obtained a tumor take of 56% and show that these xenografts maintained the histological as well as most genomic features of the parental tumors. Serum prostate-specific antigen levels were measurable only in tumor xenograft-bearing mice, but not in those implanted with either normal prostate tissue or in tumors that likely regressed. Finally, we show that a high proliferation rate, but not the pathological stage or the Gleason grade of the original tumor, was a fundamental prerequisite for tumor take in mice. This mouse xenograft model represents a useful preclinical model of primary prostate tumors for their biological characterization, biomarker discovery, and drug testing.