PDCD1 and cancer: Previous foundational studies on cancer have established that the EGFR pathway and AKT signaling play significant roles in influencing immune infiltration and the immune microenvironment within the PD-1/PD-L1 pathway.[37,38] Studies have shown that the overexpression or deletion of Claudins proteins is a key factor in malignant tumor formation, as confirmed in various cancers, including ovarian cancer and breast cancer.