The mechanism underlying
thrombocytosis is unclear; however, it is speculated
to be related to the stimulation of bone-marrow
by the cytokines (Interleukin (IL)-1, IL-6, and
Macrophage-Colony Stimulating Factor (M-CSF))
secreted from cancer cells (18,19). If this is correct,
decreased blood supply and nutrition of tumor due
to atelectasis and shunt effects may decrease the
release of these cytokines from cancer cells. In addition,
patients without atelectasis had increased blood
sedimentation rates than did atelectatic patients. The
increased sedimentation rate in non-atelectatic
patients may be related to increased fibrinogen synthesis
by well nourished cancer cells. Sahni et al.
reported that fibrinogen synthesized from cancer
cells may promote the growth of lung and prostate
cancer cells through interaction with fibroblast
growth factor-2 (FGF-2) (20).