SLFN12L (schlafen family member 12 like) is a myeloid differentiation factor involved in immune regulation and disease progression. Primary Function: SLFN12L is the human ortholog of murine SLFN4 and marks a subset of myeloid-derived suppressor cells (MDSCs) 1. Mechanism: SLFN12L expression is induced through Toll-like receptor 9 (TLR9) signaling and type I interferon-α (IFNα) pathways in response to Helicobacter infection and inflammatory stimuli 23. SLFN12L+ MDSCs suppress T cell proliferation and regulate T cell quiescence 31. Expression is downregulated during T cell activation but restored by exogenous IFNα 3. Disease Relevance: SLFN12L is associated with gastric cancer progression, correlating with intestinal metaplasia and myeloid-derived suppressor cell polarization during chr17 Helicobacter infection 42. Elevated SLFN12L expression predicts adverse prognosis and lymph node metastasis in gastric cancer patients 5. Clinical Significance: SLFN12L serves as a potential diagnostic and prognostic biomarker for sarcoidosis and gastric cancer 65. Genetic variants in SLFN12L correlate with overall survival in stage IIIA non-small cell lung cancer 7. These findings suggest SLFN12L may serve as a therapeutic target for immune modulation in cancer progression.