['Non small cell lung carcinomas (NSCLC) are known to secrete various cytokines such as VEGF (vascular endothelial growth factor), G-CSF (granulocyte-colony stimulating factor) and TGF-beta (transforming growth factor-beta) that may stimulate bone marrow activity.', 'This study reports on the relationship between serum levels of VEGF, G-CSF, TGF-beta and FDG uptake by the bone marrow in NSCLC patients.', 'Thirty-three patients suffering from newly diagnosed NSCLC who were successively referred to undergo an FDG PET scan as a part of their routine staging procedure and that did not suffer from bone metastases were included in the study. FDG bone marrow activity was determined in all patients and related to pre-treatment VEGF, G-CSF and TGF-beta serum levels.', 'Mean standardized uptake values (SUV mean) of the bone marrow ranged from 0.1 to 2.1 (mean 1.1). G-CSF, VEGF and TGF-beta serum levels ranged from 13.5 to 110 pg/ml (mean 41.4 pg/ml), from 95 to 3,221 pg/ml (mean 1,111 pg/ml) and from 269 to 615 pg/ml (mean 387 pg/ml), respectively. SUV mean values of the bone marrow significantly correlated with TGF-beta serum measurements (r = 0.621, p < 0.0001), but not with VEGF and G-CSF measurements.'] Is fDG uptake by the bone marrow in NSCLC patients related to TGF-beta but not to VEGF or G-CSF serum levels?