SPHK1 and neoplasm: We further constructed gene modules in AT2 (LUAD) and basal (LUSC) cells, which revealed that many tumor-related genes in cells from stage-I patients, including PIGR, AZGP1, BTG2, EGR1, and LMO3 in AT2 cells from LUAD (Fig. 5e), and AQP3, SPHK1, PPT1, and PDIA6 were found in basal cells from LUSC (Fig. 5f).