Fig. 7. The 3′ LTR of the provirus drives the overexpression of STAT3.

There is a normal allele of STAT3 in tumor 1A. A diagram showing the two STAT3 alleles, and their expression, is on the left. A ddPCR assay (see main text and Materials and Methods) was developed that distinguishes the transcripts from each other and from genomic DNA (which is unspliced). As shown on the right, the LTR-driven STAT3 is expressed at about a 30-fold higher level than the normal transcript.