SLC52A3 and esophageal squamous cell carcinoma: The rs13042395 is a SNP locus, located at the 5′ flanking region of the SLC52A3 gene, with a minor allele frequency (MAF) ranging from 9.30 to 36.4 % in ESCC vs. 8.28 % to 36.5 % in controls [8, 9, 17–20].