ATR and gastric cancer: On the molecular level, MSI-high gastric cancers exhibited a multigenic mutational spectrum, accumulating frameshift mutations across several critical pathways, including cell growth regulation (e.g., TGFβRII, IGFIIR, TCF4), apoptosis (e.g., BAX, FAS, CASP5), and DNA repair (e.g., hMSH3, MED1, ATR, BRCA2, RAD50) (for full names of the genes and proteins, see the abbreviation section).