Stat3 (signal transducer and activator of transcription 3) promotes cell survival/proliferation, motility and immune tolerance and is considered as an oncogene. When signaled by cytokines and growth factors, such as oncostate, the activated Stat3 is translocated into the nucleus, where the gene expression is regulated by binding to the DNA recognition site. Signosis has developed a Stat3 ELISA kit to detect Stat3 activation. Stat1 exerts a wide spectrum of functions on both tumor cells and the immune system. Stat1 is usually considered as a tumor suppressor by enhancing inflammation and triggering anti-proliferative and pro-apoptotic responses in tumor cells. Upon activated by cytokines, such as INFgamma, stat1 forms homodimers or heterodimers with Stat3 or Stat2 and binds to the response element on the promoter region of target genes. Signosis has developed a Stat1 ELISA kit to monitor Stat1 activation. While Stat3 promotes cell survival/proliferation, motility and immune tolerance and is considered as an oncogene, Stat1 enhances inflammation and innate and adaptive immunity, triggering in most instances anti-proliferative and pro-apoptotic responses in tumor cells. Despite being activated by common cytokines and growth factor receptor pathways, their activation is reciprocally regulated to redirect and balance cytokine/growth factor signals from proliferative to apoptotic, or from inflammatory to anti-inflammatory. Signosis has developed Stat3/Stat1 ELISA kit to distinguish the activation of Stat3 and Stat1.