SPP1 and cancer: The identification of many well-defined cancer gene markers (representing oncogenes), such as EGFR [13], osteopontin (SPP1) [13,14], ERBB3 [15], MALAT1 [16], S100A2 [17-19], S100A6 [20], ABCC3 [21] and ELN3 [24], as highly discriminative genes by the ECD is quite encouraging (sheet S1.A in Additional file 1).