ACVR1 and neoplasm: A GeneChip® Operating Software (GCOS) analysis confirmed that the overall expression of selected key BMP components (BMP2, ACVR1, Smad1, BMPR2, Smad5, SOX4, Id3 and ROCK1) was higher in EBV-positive NPC tumours than normal nasopharyngeal epithelium (Figure 1a) with average fold increases of 2.4 for BMP2 (p-value < 0.01), 5.2 for ACVR1 (p-value < 0.01), 5.1 for Smad1 (p-value < 0.01), 5.8 for BMPR2 (p-value < 0.01), 2.4 for Smad5 (p-value > 0.05), 14.3 for SOX4 (p-value > 0.05), 1.85 for Id3 (p-value < 0.01) and 2.24 for ROCK1 (p-value < 0.01) (Figure 1).