ACKR3 and head and neck cancer: ONCOMINE analysis results shown in Fig. 1A demonstrated that mRNA expression levels of CXCR4 and CXCR7 were upregulated in all subtypes of head and neck cancer, while CXCR2 and CXCR5 were downregulated (fold change > 1.5, p-value < 0.05).