In addition, immunohistochemistry analysis showed that JQ1 and vincristine co-operatively reduced the proportion of neuroblastoma cells positively stained by the antibody against Ki-67 (Figure 6B), a marker for cell proliferation, and co-operatively increased the proportion of tumor cells positively stained by TUNEL (Figure 6C), a marker for apoptosis. This evidence concerns the gene MKI67 and neuroblastoma.