To determine whether the T304I mutation disrupts the Polβ/XRCC1 interaction in vivo and in vitro, we used lentiviral transduction to modify the colon cancer cell line HCT116, creating stable cell lines that express either Flag-Polβ(WT) or Flag-Polβ(T304I). Here, XRCC1 is linked to malignant colon neoplasm.