CXCL6 is a pro-inflammatory cytokine associated with chemotactic and pro-angiogenic activity: a human study on apical periodontitis reported that its expression originates from inflamed gingival tissue [40], while another study reported its overexpression (fold change >100) in the odontoblastic layer of carious teeth [41]. Here, CXCL6 is linked to periapical periodontitis.