Confirmation that MCT4 can be detected in Circulating Tumour Cells (CTC) isolated from Small Cell Lung Cancer (SCLC) patients utilising the new immunofluorescence method developed in the present study. The gallery contains representative CTC harvested from 2 different patients. Operating parameters and channel identification are as defined in Figure 5. MCT4 staining in SCLC CTCs demonstrated a clear divide in expression levels between different cells of the same blood sample. Although the majority of SCLC CTCs expressed MCT4, a clear sub-population expressed MCT4 to minimal levels.