tokens: However , the ES cell system can be used as an alternative until targeted erythroleukemia cells become available .
folded_tokens: however , the es cell system can be used as an alternative until targeted erythroleukemia cells become available .
labels: O O O B-other_name I-other_name I-other_name O O O O O O O B-cell_line I-cell_line I-cell_line O O O