SLC35F6 is a solute carrier family member with emerging roles in cancer biology and cellular metabolism. Primary function: SLC35F6 localizes to lysosomes and functions as a nucleotide-sugar transporter 1, with a critical EQERLL360 sorting signal in its C-terminal region directing lysosomal localization. Mechanism: The protein negatively regulates outer mitochondrial membrane permeability and promotes cell proliferation 2, maintaining mitochondrial membrane potential in cancer cells. Disease relevance: SLC35F6 is significantly upregulated in multiple cancer types. In hepatocellular carcinoma, elevated SLC35F6 associates with poor prognosis and promotes cell growth through the miR-542-3p/SLC35F6/TP53 regulatory axis; knockdown suppresses HCC progression 3. In bladder urothelial carcinoma, elevated SLC35F6 expression correlates with worse prognosis and serves as an independent risk factor alongside TNM stage and grade 2. SLC35F6 was also identified as significantly upregulated in lung adenocarcinoma with cisplatin resistance 4. Clinical significance: SLC35F6 enhances prognostic accuracy when combined with clinicopathological factors in bladder cancer 2, positioning it as a potential therapeutic target and prognostic biomarker across multiple malignancies. Interestingly, genetic variants near SLC35F6 show cross-species associations with behavioral and temperamental traits in both dogs and humans 5, suggesting broader physiological roles beyond cancer.