Figure 2: Statistical analysis of microarray (SAM) plot of MG63 cultured on PT disks versus control. Expected differentially expressed genes are reported along the 𝑥 axis, whereas observed differentially expressed genes are along the 𝑦 axis. Downregulated genes (green dots) are located in the lower left side of the diagram; upregulated genes (red dots) are in the upper right side; genes with different expression but statistically not significant are depicted in black. Parallel lines drawn from lower-left to upper-right squares are the cut-off limits. The solid line indicates the equal value of observed and expected differentially expressed genes.