title: Prognostic significance of platelet and microvessel counts in operable non-small cell lung cancer.
abstract: BACKGROUND
  Microvessel density, an indirect measure of angiogenesis, has been shown to be an independent prognostic marker in many solid tumours including non-small cell lung cancer (NSCLC). Platelets transport and release angiogenic growth factors. Platelets are increasingly likely to adhere to tumour microvessels due to raised expression of platelet-binding proteins and stasis in blood-flow. Increased vascular permeability in tumour microvessels facilitates platelet extravasation into the extracellular matrix. Adherence and extravasation both lead to platelet activation and release of growth factors capable of instigating the angiogenic process.
  
  
  METHODS
  A total of 181 patients were identified who underwent resection of stage I-IIIa NSCLC with a post-operative survival >60 days. Patients were followed-up for a minimum of 24 months. Sections from the tumour periphery were stained for the endothelial marker CD34 (Novocastra NCL-END) using standard ABC immunohistochemistry. Chalkley counting was used to assess microvessel density.
  
  
  RESULTS
  A pre-operative platelet count greater than the median and above the normal range (>400) was associated with a poor outcome (P=0.01 and P=0.04, respectively). Tumours with an above median and high Chalkley count (upper tertile) had a worse prognosis (P=0.007 and P=0.0006, respectively). There was no association between platelet count and Chalkley count.
  
  
  CONCLUSIONS
  Platelet and microvessel counts are both potential prognostic markers for NSCLC. The role of platelets in the angiogenic process needs to be further investigated.
authors.affiliation: Department of Medical Oncology, Leicester Royal Infirmary, Welford Road, LE1 5WW, Leicester, UK.
authors.forename: G
authors.initials: G
authors.lastname: Cox
authors.forename: R A
authors.initials: RA
authors.lastname: Walker
authors.forename: A
authors.initials: A
authors.lastname: Andi
authors.forename: W P
authors.initials: WP
authors.lastname: Steward
authors.forename: K J
authors.initials: KJ
authors.lastname: O'Byrne
mesh_terms: D000328:Adult; D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000098:blood supply* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic; D015539:Platelet Activation; D010976:Platelet Count; D011247:Pregnancy; D011379:Prognosis; D016019:Survival Analysis