Ki67 immunofluorescence showed that the proportion of Ki67-positive cells in the DM1-03 group was lower than that in the DM1-04 group, while the proportion in the DM1-13-3 group was higher than that in the DM1-03 group but lower than that in the DM1-04 group (Fig. 1d, e). Here, MKI67 is linked to myotonic dystrophy type 1.