_1638002893 1638002893 brea akaviani@archbreastcancer.com Farname Inc Archives of Breast Cancer Arch Breast Cancer 2383-0433 10 31 2021 Sahar Rezaei Hemen Moradi-sardareh Mohammad-Hasan Khadem Ansari Fatemeh Kheradmand Background: The serotonin, copper, and ceruloplasmin markers are altered in various cancers, including breast cancer. It has been reported that these markers have the potential to be used in the study of cancer recurrence. The purpose of this study was to compare the levels of serotonin, copper and ceruloplasmin besides the routine breast cancer markers such as CEA and CA15-3 in the blood sample of patients with invasive ductal breast cancer, before and after chemotherapy.  Methods: This study was performed on 30 patients with breast cancer. Blood samples were taken from the patients before and after chemotherapy. Necessary data including age, tumor grade and status of Her-2, ER, PR receptors were obtained from patient records. Serotonin, CEA and CA15-3 levels were measured by ELISA method. Ceruloplasmin and copper were measured by nephelometry and colorimetric methods, respectively. Results: Results showed a decrease in serotonin, ceruloplasmin, copper, CEA and CA15-3 after treatment but only the levels of serotonin and ceruloplasmin showed a steady decrease. No significant relationship was observed between tumor grade and ER-PR, Her-2 receptors.  Conclusion: This study showed that chemotherapy resulted in steady decline in serotonin and ceruloplasmin levels but this decrease was not steady in levels of CA15-3 and CEA. Therefore, if our results are confirmed by further research, they can be considered as a viable alternative to routine markers in cancer recurrence after chemotherapy. 10 31 2021 313 317 http://creativecommons.org/licenses/by-nc/4.0 10.32768/abc.202184312-317 https://www.archbreastcancer.com/index.php/abc/article/view/412 https://www.archbreastcancer.com/index.php/abc/article/download/412/572 https://www.archbreastcancer.com/index.php/abc/article/download/412/572