Stat3, short for signal transducer and activator of transcription 3, is a nuclear transcription factor. It is a key member of the JAK/STAT signaling pathway. STAT3 regulates genes involved in cell cycle, cell survival, and immune response [4]. It has a crucial role in numerous biological processes and is associated with various diseases [1-3, 5-7].

STAT3 is broadly hyperactivated in the tumor ecosystem, both in cancer and non-cancerous cells. It inhibits the expression of immune activation regulators and promotes immunosuppressive factor production, making targeting its signaling pathway a promising cancer therapeutic strategy [1]. In liver fibrosis, its activation can have anti-or pro-inflammatory roles [2]. In breast cancer, overexpressed and constitutively activated STAT3 is involved in progression, proliferation, metastasis, and chemoresistance [3]. In pancreatic cancer, STAT3 binds to the GPX4 promoter region to promote its transcription, and thiostrepton can block GPX4 expression by regulating STAT3, inducing ferroptosis [5]. In breast cancer, PRMT6-mediated methylation of STAT3 at arginine 729 is important for its membrane localization, phosphorylation, and cancer cell metastasis [6]. In kidney disease, dysregulated STAT3 activation is detrimental, and inhibiting its activity has salutary benefits in some kidney disease models [7].

In conclusion, Stat3 is essential in regulating cell-related functions and immune responses. Through studies including gene knockout or conditional knockout mouse models (implied by genetic knockout and manipulation studies in kidney disease [7]), its role in cancer, liver fibrosis, and kidney disease has been revealed. Understanding Stat3's functions contributes to developing new therapeutic strategies for these diseases.