XRCC5 and T-cell non-Hodgkin lymphoma: First, we validated the interaction of BCAT1 with the KU70 and KU80 proteins using co-immunoprecipitation (Co-IP) in two human cell lines, the T-cell lymphoma CUTTL1 and embryonic kidney HEK 293T, expressing tagged BCAT1 (Figure 2D,E).