Here, we used specific data to show that the TLR4 gene is a biomarker for a poor prognosis of kidney renal clear cell carcinoma (KIRC), skin cutaneous melanoma (SKCM), stomach adenocarcinoma (STAD), testicular germ cell tumors (TGCTs), and uterine corpus endometrial carcinoma (UCEC) and to explore the potential signaling pathways that the TLR4 gene plays in tumorigenesis and development. This evidence concerns the gene TLR4 and gastric adenocarcinoma.