Confirmation of MSI/MSS status of cell lines and MRE11 protein analysis. A and B. We performed PCR using fluorescently labeled primers specific to BAT-25 (A) or BAT-26 (B) and then performed fragment analysis using Peak Scanner Software (Applied Biosystems). We observe that MSS cell lines (black) are more consistent with regard to size an allelic variation than the MSI cell lines (grey) and confirm the MSI/MSS status previously reported for these cell lines. (C) Western Analysis of MSI and MSS CRC cell lines confirms that Mre11 levels are reduced or absent in MSI cell lines, but are normal in MSS cell lines. Lysates from the normal immortalized colon epithelial cell line, INT407, serves as the normal tissue control. EP and LP refer to early or late passage of HCT116 cells.