ALDH1A1 and neoplasm: Besides, aldehyde dehydrogenase 1 A1 (ALDHA1) activity was a promising choice for bladder CIC accumulation.43 However, sorting markers were not quite consistent among different clinical samples and cell lines, causing the complexity and flexibility of identification process.44 In our work, bladder cancer-initiating T24 sphere cells were gained from specific culture condition and identified to possess CIC characters, including chemo-resistance, self-renewal, quiescence, differentiation and tumor initiation (Figure 1 and Supplementary Figure S1).