9031
Our findings suggest that non-clonal progenitor cells persist in some RARS cases, that erythroid progenitors show mosaicism, and that ringed sideroblasts may be derived from an abnormal clone involved in the pathogenesis of this disease.
 erythroid progenitors, RARS, ringed sideroblasts, non-clonal progenitor cells
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 erythroid progenitors, RARS, ringed sideroblasts, non-clonal progenitor cells