STAT1 and breast cancer: However, it worth noting that a recent study has shown that LRRC31, a tumor suppressor protein, can directly bind Ku70/Ku80 to inhibit DNA repair and sensitizes breast cancer brain metastasis to radiotherapy.42 Furthermore, we have observed that upon VAV2 expression alternation in ESCC cells, the expression pattern of some genes in MYC target, E2F target, apoptosis, and DNA repair pathways including homologous recombination (HR) pathway also changed, which might at least in part be attributable to the STAT1 expression or activation change.