Breast cancer is a prevalent disease that has a detrimental effect on women's health and is one of the top causes of mortality due to cancer on a global scale. Recent research has demonstrated that the pattern recognition receptor known as C-type lectin domain family 4 member E (CLEC4E) may recognize related proteins produced during necrotic cell death, cholesterol crystals, and b-glucosylceramide released by injured cells. CLEC4E is expressed by phagocyte cells. In the current investigation, the concentration of CLEC4E was measured in the sera of thirty-two female patients with malignant breast tumors before they had chemotherapy; thirty-two female patients with benign breast tumors (pathological control group); and thirty-two healthy females served as the control group. The most elevated level of CLEC4E was found in the sample of a cancer patient who was in the third stage of the disease and had a history of breast cancer in their family. During the course of chemotherapy, CLEC4E levels steadily went down, which is an indication that the body responded favorably to the treatment and that fewer cancer cells were present. CLEC4E levels were found to be significantly lower in the group of breast cancer patients who had received a planned amount of chemotherapy. On the other hand, CLEC4E levels were found to be marginally lower in the group of healthy controls, which suggests that CLEC4E may be a possible biomarker for the diagnosis and prognosis of breast cancer. According to the findings of this study, CLEC4E has the potential to be used as a hopeful diagnostic marker between malignant and benign breast tumors, even after the malignant tumor has been surgically removed. In addition, CLEC4E has the potential to be an effective tool for monitoring patients' responses to treatment throughout the various phases of chemotherapy. It may be useful to study the possibility of this parameter in diagnosing tumor infection and determining the stage of the cancerous tumor, which may contribute to the designation of CLEC4E as a new marker for this kind of cancer, and evaluating the levels of CLEC4E in patients with breast tumor when diagnosing and before receiving surgical treatment may be useful for this purpose.