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We examined bone marrow cells by reverse transcriptase-polymerase chain reaction ( RT-PCR ) to detect residual PML/RAR alpha mRNA -containing cells following treatment with all-trans retinoic acid ( ATRA ) and cytotoxic chemotherapy in a patient with APL .
 PML/RAR alpha mRNA -containing cells, PML/RAR alpha mRNA
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:
 PML/RAR alpha mRNA -containing cells, PML/RAR alpha mRNA