Mast cells correlate with angiogenesis and poor outcome in stage I lung adenocarcinoma.

Angiogenesis is in part related to mast cells. However, the biological significance of mast cells within lung carcinoma remains unclear. Immunohistochemistry was used to stain for tryptase, CD34 and vascular endothelial growth factor (VEGF) in 85 cases of stage I nonsmall cell lung carcinoma. VEGF was found in 33 of 53 adenocarcinomas and 14 of 32 squamous cell carcinomas. Cases of adenocarcinoma had significantly higher mast cell counts than those of squamous cell carcinoma. In adenocarcinoma, mast cell counts in VEGF-positive tumours were significantly higher than in VEGF-negative tumours, whereas in squamous cell carcinoma they were not. Good correlation was observed between intratumoural mast cell counts and microvessel counts. Double staining showed most intratumoural mast cells expressed VEGF. Importantly, only in lung adenocarcinoma, members in the high mast cell count group had significantly worse prognosis than those in the low mast cell count group. It is concluded that tumour-released vascular endothelial growth factors may be related to mast cell accumulation, intratumoural mast cells may produce vascular endothelial growth factor, and stromal mast cells correlate with angiogenesis and poor outcome in stage I lung adenocarcinoma.