Invasive ductal carcinoma is the most common type of invasive breast cancer. In cases where axillary lymph node metastases are diagnosed through screening, they can be found in up to 25% of cases, and in symptomatic cases, up to 60% of cases. The clinical detection accuracy of axillary lymph node metastases is only 33%. Accurate staging of lymph nodes in breast cancer patients is crucial for both prognosis and treatment. Ultrasonography is much more sensitive than physical examination alone for determining axillary lymph node involvement in breast cancer staging. Fine needle aspiration biopsy or core biopsy is diagnostic in lymph nodes that cannot be clarified solely by ultrasonography or are suspicious. Although biopsy sampling yields high diagnostic rates, it requires an experienced pathologist and sometimes takes weeks to yield results. Therefore, there is a need for faster and less costly diagnostic methods for diagnosing axillary metastases. Among thyroid cancers, papillary thyroid carcinomas, a malignancy in which the lymph node washout method is used to determine lymph node metastasis, are the most common. In papillary thyroid cancer patients, washout sampling of neck lymph nodes by fine needle aspiration, searching for thyroglobulin, a protein normally found in thyroid tissue, is considered one of the most valid methods for detecting lymph node metastasis in this cancer. In recent years, immune checkpoint molecules associated with cancer have been widely used as biomarkers and agents in both diagnosis and treatment for cancer patients. There are numerous publications in the literature regarding the expression of immune checkpoint molecules such as Programmed cell death protein 1 (PD-1), Programmed death ligand 1 (PD-L1), and The cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) on the cell surface of breast cancer patients. Although the natural soluble forms of receptors and ligands of immune checkpoint molecules exist and they are important components of immune regulation, their exact mechanisms of action have not yet been determined. There are five studies in the literature evaluating the status of soluble immune checkpoint molecules in breast cancer patients, with one being a review article. It is highly likely that immune checkpoint molecules found on both the cell surface and soluble in blood and body fluids are also present in tumor metastatic regions. There is no study using these immunological biomarkers to determine metastasis in invasive ductal carcinoma patients with metastatic axillary lymph nodes ın the literature. In this study, the investigators will evaluate the soluble levels of immune checkpoint molecules in washout fluids obtained from metastatic axillary lymph nodes and benign lymph nodes in patients with invasive ductal breast carcinoma, and will assess the effectiveness of these immune checkpoint molecules and the washout method in diagnosing metastasis.