S1PR1 and neoplasm: Given that S1PR1-STAT3 signaling is crucial for tumor metastasis20,21 and our results showed that VEGF-A, downstream of the STAT3 pathway, was correlated positively with ERO1α expression, we futher determined expression of STAT3 and phospho-STAT3 (p-STAT3) in ERO1α-knockdown or ERO1α-overexpressing cells using western blots (Fig. 6d).