It is noteworthy that a variable that has been underexplored in CDH1 methylation studies in breast cancer is the role of tumor-infiltrating lymphocytes (TILs), despite Lombaerts et al. [5] first describing lymphocyte infiltration as a factor to consider in 2004 due to its potential influence on the detection of CDH1 promoter methylation in breast tumors. This evidence concerns the gene CDH1 and breast cancer.