In conclusion, we demonstrated the Oligomycin A inhibitory effects of CDDO-Im on triple-negative breast cancer with a potential to target cancer stem cell subpopulation, as evidenced by inhibition of CD242/low/EpCAM+ cells and tumorsphere formation. The present study along with previous reports raises the possibility of using CDDO-Im as a potent anti-cancer agent against triple-negative breast cancer. Since cancer stem cells may be responsible for tumor recurrence and metastasis, the inhibition of multiple stem cell signaling pathways by CDDO-Im might alleviate problems of chemoresistance and metastasis. Because of the concentration-dependent functions of CDDO-Im, preclinical studies to select the proper concentrations to induce anti-cancer activity will be the next step for developing CDDO-Im as a therapeutic agent for triple-negative breast cancer. Primary tracheal tumors are very rare, representing only up to 0.2% of all respiratory malignancies. This is particularly true in the paediatric population. The most common tracheal neoplasm reported in children is mucoepidermoid carcinoma, a salivary gland-type cancer. The mucoepidermoid tumors are histologically heterogenous low-grade tumors that grow locally, without metastasis. It is usually identified by a characteristic translocation/fusion transcript at t. Due to their rarity, the characteristics and biology of these neoplasms remain poorly understood. However, it has been proposed that tracheal tumors may originate from niche cells that reside in the respiratory epithelium, glands or mesenchymal niches. These could be either a population of tissue stem cells, transformed progenitor cells or cancer stem cells. Normal stem cells and tumorigenic cells share many resemblances with regard to gene expression profiles, morphology and both have extensive proliferative potential with the ability to give rise to new tissues. The growth of solid cancers has been suggested to be driven by what has been generally termed ‘cancer stem cells’, reported from malignant tumors of various tissues such as lung, pancreas, prostate, colon and breast. Normal stem cells and CSCs show also similarities with regard to their dependencies on sonic hedgehog, Notch and Wnt pathways. A presence of stem-like cells detected in also benign tumors, as shown in the present paper, is in accordance with a previous report by Xu and colleagues studying pituitary adenoma. However, stem cells have so far not been demonstrated in transformed tissues from the human upper respiratory tract. We here identified and characterized the expanded primary cultures from a benign paediatric mucoepidermoid tracheal tumor. To date, tissue specific stem cells have not been demonstrated in transformed tissues from the human upper respiratory tract. In the present study, we identified and expanded mesenchymal stem cell-like cells in primary cultures from a rare benign paediatric mucoepidermoid tracheal tumor.