SPINK1 and hepatocellular carcinoma: Given the elevated expression levels of SPINK1 in sub-clusters numbered 5, 7, 8, 11, 12, 14, 17, 18, 19, 20, 21, 22, 23, 24, 27, 28, 29, 30, 31, 32, and 33 (Supplementary Figure S1C), we integrated these sub-clusters as SPINK1-high HCC cells and integrated the remaining sub-clusters as SPINK1-low HCC cells.