Preclinical studies and studies of other cancers than SCLC have shown that FLT-SUVmax reduces more rapidly and/or more pronounced than FDG-SUVmax during therapy (Kahraman et al. 2012; Jensen et al. 2010; Mudd et al. 2012; Kishino et al. 2012), but individual treatments may affect FDG- and FLT-uptake changes differently (Jensen and Kjaer 2015), and thus should be investigated separately. Here, SMUG1 is linked to small cell lung carcinoma.