Figure 1.

Rac GTPase expression and activity is higher in neuroblastoma lacking MYCN amplification. (A) Active Rac levels detected by western blot in the indicated neuroblastoma cell lines. Positive (GTPγS) and negative (GDP) controls of the activity assay are shown. The black vertical line between the controls and samples indicates that controls are from a different part of the same gel. (B) Quantification of active Rac levels in indicated neuroblastoma cell lines (intensity of active Rac divided by total Rac, n = 4 independent experiments). (C) Comparison of Rac1 expression and MYCN amplification status reveals that high level Rac expression is significantly associated with non MYCN amplified tumors. Data were accessed from the OncoGenomics database of the National Cancer Institute (https://pob.abcc.ncifcrf.gov/cgi-bin/JK).³² Patients were divided into high and low Rac1 expression groups by median-centered log 2 ratios. Statistical significance was determined by Fisher's exact test comparing the numbers of tumors in each category.