Distant organ metastasis of prostate cancer is a puzzle, and various theories have successively arisen to explain the mechanism of lethal cancer progression. While perhaps agreeable to many cancer biologists, the very statement of “seed and soil” proposed by Stephan Paget in 1881 is arguably still the major statement for organ-specific cancer metastasis. Since recent studies showed important correlations of regulation of cancer cells and the microenvironment, exosomes from cancer and stromal cells seem to create another important niche for metastasis. Stromal cells pretreated with exosomes from metastatic cancer cells increase the potential of change stromal cells. The poorly metastatic cancer cells could also enhance malignancy through transfer of proteins, microribonucleic acid and messenger ribonucleic acid to recipient cancer cells.
Cross-talk between tumor and microenvironment regulates cancer progression via exosome as communication tool. Benign PC released exosomes content factors that stimulate environmental changes in the inhibition of other cancer progression. By contrast, exosomes released by malignant PC content signals to alter stromal cells for further malignant cancer progression. The feedback of exosomes from stromal cells could enhance cancer metastasis progression.