Emerging genomic evidence suggests that non-mutagenic promoters shape the global distribution of esophageal squamous cell carcinoma (ESCC). One suspected promoter is a group of minuscule needle-shaped glass fragments as outgrowths on edible weeds, millet bran, and wheat bracts, which in a bolus of food could scarify a narrowed gullet in high-risk regions of South Africa, Iran, and northern China. Repeated injuries and chronic inflammation of esophageal epithelium caused by these glass needles are analogous to cosmetic micro-needling in dermatology-stimulating collagen and elastin via wound-healing cascades. While tumors can be unhealed wounds and siliceous "micro-needles" from wheat bracts have been linked to the high ESCC risk in wheat-based eaters in semi-arid northern China, we here report abundant needle-shaped diatom frustules (siliceous cell walls of diatoms, aka "glass boxes") in trash fish-related food samples from high-ESCC regions of coastal southeastern China. Through a preliminary feeding trial conducted on rats, we found that needle-shaped diatom frustules may be more likely to lodge in the esophageal epithelium of rodents than round-shaped ones. Diatom needle contaminants in the diet may underlie the ESCC epidemic in coastal southeastern China, where dietary culture allows the guts of trash fish to enter human food.
Wu et al. (Mon,) studied this question.