SOAT1 and neoplasm: To further confirm the role of two Stat-5 isotypes in tumor-induced CD4+ T cell demise, Jurkat T cells were over-expressed with wild-type Stat-5A/Stat-5B, C-terminal truncated dominant negative Stat-5 (Stat-5A713 and Stat-5B718) or constitutively active Stat-5A (Stat-5A1*6) genes (Fig. 4B) and then incubated with tumor-culture supernatants.