Although it was reported that tumorigenic retinal stem‐like cells can be identified from primary human RB tumors and these cells also have high BMI1 expression (Zhong et al., 2007), it would be of a particular interest to determine whether BMI1 is involved in RB stem‐like cell maintenance given the well‐defined function of BMI1 in stem cell biology. Here, BMI1 is linked to retinoblastoma.