Needle-shaped diatom frustules in food as a possible promoter of esophageal squamous cell carcinoma in coastal southeastern China: A pilot study.

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.