Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Cowden syndrome ?
    ### Response:
    What causes Cowden syndrome? Most cases of Cowden syndrome are caused by changes (mutations) in the PTEN gene. PTEN is a tumor suppressor gene which means that it encodes a protein that helps keep cells from growing and dividing too rapidly or in an uncontrolled way.
    