To gain insight into the role of HVEM/BTLA/CD160/LIGHT pathway in the net balance of co-inhibitory and costimulatory signals provided by tumor cells to T cells and NK cells, HVEM gene was mutated in A20 leukemia cells and the anti-tumor response was evaluated in the context of hybrid resistance and parental tumor implantation into F1 recipients. The gene discussed is TNFSF14; the disease is leukemia.