SLC12A8 (solute carrier family 12 member 8) functions primarily as a specific nicotinamide mononucleotide (NMN) transporter that plays a critical role in cellular NAD+ metabolism 1. The protein facilitates sodium-dependent NMN uptake into cells, particularly in the small intestine where it is highly expressed and regulated by NAD+ levels 1. SLC12A8 is essential for maintaining intestinal NAD+ homeostasis, with deficiency significantly decreasing NAD+ levels in jejunum and ileum tissues 1. Beyond its metabolic functions, SLC12A8 has emerged as an important factor in cancer biology. The gene is upregulated in multiple cancer types including colorectal cancer, non-small cell lung cancer, and bladder cancer, where high expression correlates with poor patient prognosis 234. Mechanistically, SLC12A8 promotes cancer progression by facilitating epithelial-mesenchymal transition, reducing apoptosis, decreasing reactive oxygen species production, and activating JAK/STAT signaling pathways 24. Additionally, SLC12A8 upregulation contributes to chemotherapy resistance, particularly to oxaliplatin treatment 2. The protein has also been identified as a potential therapeutic target for immunotherapy due to its associations with immune checkpoint genes and tumor microenvironment regulation 5.