MELK and neoplasm: While HMEC-DD-NeuT cells expressing the empty vector failed to form tumors in mice, overexpression of either WT- or myr-MELK in these cells drove tumor formation with 100% penetrance within 2 months (Figure 4—figure supplement 1), demonstrating that overexpression of MELK was able to confer the tumorigenicity of HMEC-DD-NeuT cells.