MLH1 and breast cancer: Compared to MMR-wt tumors, MMR-altered breast cancers exhibited a higher frequency of mutations in several key driver genes, including but not limited to TP53 (61.0% vs. 34.5%), KMT2C (26.8% vs. 6.0%), MLH1 (26.8% vs. 0.0%), PTEN (24.4% vs. 6.0%), and NF1 (22.0% vs. 4.1%) (Figure 4A,B).