Immunohistochemistry for Protein Expression

Immunohistochemistry staining was performed as previously described^{45 (link)}. The following primary antibodies (anti-METTL1, Proteintech, 1:2000 dilution; Anti-WDR4, Abcam, 1:1000 dilution; Anti-Ki67, Proteintech, 1:8000 dilution; Anti-RPTOR, Proteintech, 1:500 dilution; Anti-pS6K1, Cell signaling technology, 1:1000 dilution; Anti-pULK1, Affinity, 1:1000 dilution; Anti-p4EBP1, Cell signaling technology, 1:1000 dilution) were used for detection of indicated protein expression. IHC staining was evaluated as H-score using QuPath (v0.2.3) by recording the staining intensity and the proportion of the cells with positive staining^{46 (link)}. Tissues with H-score of ≧100 were defined as high expression samples, and tissues with H-score below 100 were defined as low expression samples. For survival analysis, patients were stratified into four groups based on their relative levels of H-scores: (>75%, 50–75%, 25–50%, and 0–25%).