In esophageal squamous cell carcinoma (ESCC), diffuse cytoplasmic expression of SLC52A3 (which codes for riboflavin transporter-3) can be observed in tumoral tissue compared to normal cells; additionally, in a cohort of ESCC patients, the nuclear expression of SLC52A3 was associated with poor prognosis (164). This evidence concerns the gene SLC52A2 and esophageal squamous cell carcinoma.