Consistent with tumor data, RNA-seq showed upregulation of tumor enhancing pathways only in cells that enhanced tumor progression.<h4>Discussion</h4>The results indicate that in a breast cancer xenograft model, APOBEC3A and APOBEC3H Haplotype I are more likely to contribute to enhanced tumor progression than APOBEC3B. Here, APOBEC3B is linked to breast carcinoma.