BTG3 (BTG anti-proliferation factor 3) is a tumor suppressor gene that functions as a negative regulator of cell cycle progression and proliferation. BTG3 overexpression impairs serum-induced cell cycle progression from G0/G1 to S phase and induces cell cycle arrest at G2/M phase 1. The protein promotes autophagy and can be targeted by microRNAs like MIR106A-5p, which suppresses BTG3 expression leading to autophagy inhibition and malignant phenotypes in nasopharyngeal carcinoma 2. BTG3 expression is frequently downregulated in multiple cancer types through promoter hypermethylation, including renal cell carcinoma and gastric cancer 34. In renal cell carcinoma, TRIM65 promotes tumorigenesis by inducing K48-linked ubiquitination and degradation of BTG3, relieving G2/M phase arrest 1. BTG3 also functions in antiviral responses, inhibiting porcine epidemic diarrhea virus replication by promoting viral S2 protein degradation through autophagy and proteasome pathways 5. The gene serves as both a potential biomarker for cancer prognosis and a therapeutic target, with its restoration through demethylating agents like genistein showing promise for cancer treatment 34.