12068
To analyze the effects of ectopic expression of spi-1 on the proliferation/differentiation of human myeloid leukemia cells , K562 cells were stably transfected with a spi-1 expression vector .
 spi-1, human myeloid leukemia cells, K562 cells, spi-1 expression vector, spi-1
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:
 spi-1, human myeloid leukemia cells, K562 cells, spi-1 expression vector, spi-1