This model provides prostates with tumors in 4 different development periods.

Features:

• The 1st development : Beginning, a little big but the prostates still works well.
• The 2nd development : Some hard tubers can be observed in the top right quadrant of prostate. It's the beginning of the tumors.
• The 3rd development : The tumor is proliferating, and the previous tubers become bumps.
• The 4th development : The prostates is all replaced by tumors, the surface become more rough and harder than before.