PLA2G2A and psoriasis: Although the causal relationship between the fecal abundance of a specific Helicobacter or other bacteria species and the skin phenotypes in Pla2g2a–/– mice remains to be elucidated, our results nonetheless provide strong support for the notion that regulation of gut microbiota by sPLA2-IIA, a Paneth cell–derived antibacterial protein, is linked to altered susceptibility to skin carcinogenesis and psoriasis.