RB1 and cancer: Therefore, we detected the relative expression of Rb1 protein in cancer tissues and cells and found that the expression of Rb1 protein in cancer tissues was significantly lower than that in adjacent tissues, and the relative expression of Rb1 protein in Y79 and HXO-Rb44 cells was also lower than that in APRE-19 cells, suggesting that miR-215 may also regulate the expression of Rb1 protein in Rb.