Moreover, U2OS osteosarcoma cells depleted of PRPF8 with two independent siRNAs and monitored by phase-contrast time-lapse microscopy spend >120 min in mitosis, as opposed to control cells, in which mitosis lasts, on average, <60 min (Fig. 4b; Additional file 4a). Here, PRPF8 is linked to osteosarcoma.