Common classification schemes for PCB congeners and the gene expression of CYP17, CYP19, ESR1 and ESR2

► We sought to explore if the expression of four key genes involved in sex steroid metabolism was affected by human exposure to PCB congeners. ► We examined 139 females using mixed models analyses, adjusting for confounders. ► We found that CYP 19 expression is up-regulated by dioxin-like PCB congeners, traditionally seen as anti-estrogenic. ► This finding confirms previous work suggesting possible links between AhR and ER signaling pathways.