ALDH1A1 and breast cancer: Elevated ALDH levels, particularly in ovarian, lung, liver, and breast cancer cells, are potential indicators of malignant tumors.68 Moreover, high ALDH levels contribute to increased resistance of cancer cells to cytotoxic drugs and other treatment modalities, exemplified by the resistance conferred by overexpression of ALDH1A1 and ALDH3A1 to cyclophosphamide.69,70 The ALDH1 isoenzyme serves as an identification marker in both normal and cancer stem cells, underscoring the importance of monitoring ALDH activity in cancer cells for targeted therapeutic interventions.71