For example, DNAse2, DNAse1L2, and TREX2 in oral epithelial cells;[42, 43] DNAse1 and DNAse1L3 in salivary glands;[44] and other nucleases such as ‘deoC’ or ‘nuc’ are secreted by oral microbiota.[45, 46] Additionally, the aberrant activity of nucleases such as DNAse1, DFFB, XPF/XPG, etc., has been reported in GC patients.[47, 48] Thus, the perceived variation in ScfDNA fragment profiles in healthy and disease states could be explained by a disruption of nuclease activity within the oral cavity. This evidence concerns the gene ERCC5 and gastric cancer.