Potential gene biomarkers of tumor cell susceptibility to arsenic trioxide. A total of 209 genes (242 gene probes) were identified with significant expression association with tumor cell susceptibility to arsenic trioxide across 58 tumor cell lines (FDR < 0.05). Cell line numbers are displayed on the X-axis. For the complete list of tumor cell lines refer to Additional File 1. Gene expression values were mean centered and high relative expression is indicated in red and low relative expression indicated in blue.