Optimisation of operating parameters for determination of MCT1 by immunofluorescence (IF) in control cell lines spiked into volunteer blood. The figure contains a gallery of images obtained by the CellSearch system in 4 different channels from a total of 9 different cells utilising discrete markers to characterise the cells. Images were generated at the optimum integration time of 0.4 seconds for detection of MCT1. Anti-cytokeratin-phycoerythrin (CK-PE) labels the intracellular protein cytokeratin (specific for epithelial cells), 4′-6-diamino-2-phenylindole (DAPI) the cell nucleus and anti-CD45-allophycocyanin (APC) labels leukocytes to allow discrimination between tumour cells. An additional channel contains a pseudo-coloured composite image of the DAPI and CK-PE stains. MCT1 was only detected in the 4th channel in the positive control cell line K562 (see Figure 1) that had been stained with MCT antibody, but was absent in unstained K562 cells and the negative control cell (see Figure 1) MDAMB231 stained for MCT1.