tokens: In contrast to MEL cells , however , K562 cells acquired a macrophage-like morphology and exhibited a complete failure to generate benzidine-positive cells .
folded_tokens: in contrast to mel cells , however , k562 cells acquired a macrophage-like morphology and exhibited a complete failure to generate benzidine-positive cells .
labels: O O O B-cell_line I-cell_line O O O B-cell_line I-cell_line O O B-other_name I-other_name O O O O O O O B-cell_line I-cell_line O