Li et al. found that arsenic trioxide (ATO) can increase the expression of transcription factor GCM1, which in turn increases the expression of syncytin-1 and its receptor SLC1A5, mediating cell fusion, inducing the formation of the polyploid giant cancer cells (PGCCs) in colorectal cancer, promoting the migration, proliferation and invasion of colorectal cancer cells. Here, GCM1 is linked to colorectal cancer.