Correlation Between Serum TK1 and Pathological Remission of Breast Cancer With Neoadjuvant Chemotherapy

This study is looking at whether a blood marker called TK1 (thymidine kinase 1) can predict how well breast cancer responds to chemotherapy given before surgery (neoadjuvant chemotherapy). By measuring TK1 levels before and during chemo, researchers hope to find a simple blood test that predicts treatment success. **You may be eligible if...** - You have been diagnosed with breast cancer confirmed by biopsy - You have completed a full course of neoadjuvant (pre-surgery) chemotherapy - You then had surgery and your post-surgery tissue was analyzed - You have complete MRI and blood TK1 measurements at baseline and after 2, 4, and 6 cycles of chemotherapy **You may NOT be eligible if...** - Your breast cancer had already spread to distant organs (Stage IV) at first diagnosis - You have another separate primary cancer Talk to your doctor to see if this trial is right for you.