JAK3 and neoplasm: Interestingly, when CD4+ cells were cultured in presence of theaflavin-pretreated tumor cell supernatants, significant protection towards IL2Rγc/Jak-3/Stat-5 signaling i.e., up-regulation of γc expression, Jak-3/Stat-5 association and phosphorylation as well as nuclear localization of Stat-5 (Fig. 3B–E), was observed in CD4+ T cells, which offered them relive from the apoptotic insult that was observed with untreated tumor supernatant (Fig. 2B).