S1PR1 and lung carcinoma: Kaplan-Meier plotter database also showed that low expression of S1PR1 was an independent risk factor for poor prognosis of lung cancer (overall survival, HR = 0.7, P = 6.9e-08; recurrence-free survival, HR = 0.71, P = 0.00035), but not related to post-progression survival in lung cancer (HR = 0.82, P = 0.14) (Fig. 2m–o).