11851
However, in differentiating erythroid cells , which must incorporate high levels of iron to sustain hemoglobin synthesis , and in macrophages , which are involved in iron storage, transcriptional regulation seemed to be a relevant mechanism.
 protein: hemoglobin; cell type: macrophages; cell type: differentiating erythroid cells
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: hemoglobin, macrophages, differentiating erythroid cells 
Answer:
 protein: hemoglobin; cell type: macrophages; cell type: differentiating erythroid cells