Colorectal cancer biomarkers: To be or not to be? Cautionary tales from a road well travelled

Figure 1 Stability of insulin-like growth factor binding protein 2 and matrix metalloproteinase 9. A: Standard curves for insulin-like growth factor binding protein 2 (IGFBP2) and matrix metalloproteinase 9 (MMP9) over an 18 mo period indicates that the assays were stable over time; B: IGFBP2 and MMP9 stability after storage for 18 mo in liquid nitrogen and at -80 °C (n = 10 patients); C: Stability of IGFBP2 and MMP9 following three freeze/thaw cycles. All data are represented as average ± standard deviation. F/T: Freeze/thaw cycles. ^aP < 0.05 when compared to samples measured immediately.