Snail, a zinc-finger transcription factor, plays a critical role in epithelial-mesenchymal transitions (EMTs), which are essential for embryonic development and tumor progression. Beyond inducing EMT, Snail also inhibits cell cycle progression and enhances resistance to cell death. This study demonstrates that Snail promotes changes in cell shape over cell division, suggesting that while proliferation is crucial for tumor formation, it may not be necessary for malignancy. Snail's resistance to cell death provides a selective advantage to cells during embryonic development and tumor progression, enabling them to migrate, invade, and form metastases. The research shows that Snail represses the expression of Cyclin D2 and increases p21/Cip1, which are key regulators of the G1/S checkpoint. Additionally, Snail activates survival pathways such as the MEK/Erk and PI3K/Akt pathways, which help cells resist apoptosis. Snail also confers resistance to cell death induced by pro-apoptotic signals like TNF-α. In chick embryos, Slug, the Snail homolog, behaves similarly to Snail in mice, regulating cell cycle progression and survival in the neural tube. These findings highlight the dual role of Snail in promoting cell shape changes and resisting cell death, which is essential for both embryonic development and tumor progression.Snail, a zinc-finger transcription factor, plays a critical role in epithelial-mesenchymal transitions (EMTs), which are essential for embryonic development and tumor progression. Beyond inducing EMT, Snail also inhibits cell cycle progression and enhances resistance to cell death. This study demonstrates that Snail promotes changes in cell shape over cell division, suggesting that while proliferation is crucial for tumor formation, it may not be necessary for malignancy. Snail's resistance to cell death provides a selective advantage to cells during embryonic development and tumor progression, enabling them to migrate, invade, and form metastases. The research shows that Snail represses the expression of Cyclin D2 and increases p21/Cip1, which are key regulators of the G1/S checkpoint. Additionally, Snail activates survival pathways such as the MEK/Erk and PI3K/Akt pathways, which help cells resist apoptosis. Snail also confers resistance to cell death induced by pro-apoptotic signals like TNF-α. In chick embryos, Slug, the Snail homolog, behaves similarly to Snail in mice, regulating cell cycle progression and survival in the neural tube. These findings highlight the dual role of Snail in promoting cell shape changes and resisting cell death, which is essential for both embryonic development and tumor progression.