3191
From life - table analyses of these patients , we estimated that the incidence of secondary chondrosarcoma in patients who have Ollier disease is about 25 per cent at the age of forty years , and that malignant degeneration is almost a certainty in patients who have Maffucci syndrome .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None