{HEAD ~ These anthracycline analogs} show {TAIL ~ high cytotoxicity} in vitro against several tumor cell lines 
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{ HEAD ~ These anthracycline analogs } show { TAIL ~ high cytotoxicity } in vitro against several tumor cell lines
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH