however , in the great majority of hcc , viral integrations are in different cellular dna sites in different hcc , integrations are not within domains of known protooncogenes , and integrations are not found in some 10 to 15 % hepadnavirus-associated hcc , suggesting that persisting viral sequences are not directly involved in the development of these hcc as viral sequences are for tumors caused by viruses with oncogenes or viruses that act by a `` '' promoter-insertion '' '' mechanism .
C0007634
cellular
C0086860
-insertio