WFDC2 and cancer: This early response of DUSP6 to ERK activation could explain the apparently contradictory activation of ERK by HE4 in cancer cells (Lu et al., 2012; Zhu et al., 2013; Ribeiro et al., 2016; Lee et al., 2017) and our current results here showing HE4 upregulation of DUSP6 expression leading to suppression of ERK phosphorylation in PBMC subsets.