Many researchers have discovered that the abnormal expression of transcription factors is closely correlated with malignant tumor onset and development, and among these transcription factors, Snail is a classic example that shows high levels of expression in several types of solid tumors [3–6]; Snail can induce epithelial-mesenchymal transition (EMT) [7], resulting in cancer cell invasion and metastasis and, consequently, leading to death. The gene discussed is SNAI1; the disease is cancer.