Abstract: OBJECTIVE: Local invasion is a leading cause of death in patients with lung cancer. To date,there has been no report on distribution of VEGF,EGFR and serum protein in invasive tissues of lung cancer using in vivo cryotechnique (IVCT) method. METHODS: The human A549 cell line from a non-small cell lung cancer (NSCLC) was used and cells were subcutaneously injected to the dorsal flank of nude mice. In vivo tumor samples were prepared by IVCT method. At the same time,protein distribution of albumin,IgG,IgM,VEGF and EGFR were examined by immunohistochemistry method. RESULTS: The distribution of albumin and IgG in connective tissues around the tumor mass,blood vessels,interstitium and extracellular matrix of NSCLC's invasive parts can be clearly observed by using the IVCT method. IgMs were mainly located in connective tissues around the tumor mass and blood vessels,but their distribution could not be observed in extracellular matrix of cancer cells. VEGF protein was located in cytoplasm of lung cancer cells,and it had fine granular morphology,but there was no distribution of EGFR in cytoplasm or membrane of cancer cells. CONCLUSION: The immunodistribution of different molecular weight of serum proteins in connective tissues around the tumor mass,blood vessels,interstitium and extracellular matrix can be clearly observed. The permeability of NSCLC's invasive part for albumin,IgG1 and IgM in extracellular matrix mainly depended on their respective molecular weights,but not on the protein distribution of VEGF and EGFR.

Key words: in vivo cryotechnique, NSCLC, serum protein, immunohistochemical analysis