Increased aldehyde dehydrogenase 1 (ALDH1) levels are associated with chemo-responsiveness in breast cancer patients treated with taxane–adriamycin–cyclophosphamide regimen

BACKGROUND: Increased plasma aldehyde dehydrogenase 1 (ALDH1) levels have been proposed to predict cancer chemore- sistance. However, studies have reported inconsistent results, depending on the type of cancer cells used. OBJECTIVE: This study aimed to investigate the correlation between plasma levels of ALDH1 and chemotherapy responses to the taxane–adriamycin–cyclophosphamide (TAC) regimen in breast cancer patients. METHODS: Thirty breast cancer patients who underwent chemotherapy using the TAC regimen were included in this study. Blood sampling was performed before chemotherapy was initiated and after the first and third cycles of chemotherapy adminis- tration. After 3 cycles of chemotherapy, patients were categorized as non-responsive if the tumor size was reduced <30%, if the tumor size remained the same or increased, or if any new tumors were discovered. Patients were defined as responsive after 3 cycles of chemotherapy if the tumor mass disappeared, if the tumor size was reduced by at least 30% of the initial size and if no new tumors were found. RESULTS: Among the 30 patients, only five were responsive to the TAC regimen. The clinical response to TAC was not correlated with the patient’s age, cancer grading, or tumor stage. A change in the ALDH1 levels was observed after the third cycle of TAC administration, with significantly higher ALDH1 levels observed in responsive compared with non-responsive patients (p < 0.05). CONCLUSION: The results of this study may indicate a role for ALDH1 in chemoresponsiveness, rather than chemoresistance, for the TAC regimen in breast cancer patients. Further research remains necessary to confirm this result.