30669
From these data and based on the concept of cellular heterogeneity , we hypothesize a supportive role of oestrogen in the propagation of thyroid stem / progenitor cells leading to a selection of a progeny of growth - prone cells with a decreased differentiation .
 oestrogen
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 oestrogen