GSPT1 and colonic neoplasm: Figure 1C shows representative examples of immunohistochemically stained sections for low (up) and high (down) levels of nuclear GSPT1. The mRNA level of GSPT1 was also determined in four colon cancer cell lines. As shown in Figure 1D, the HCT116 and SW480 cell lines showed significantly higher levels of GSPT1 than the HT29 and SW620 cell lines.