APPLICATIONS OF IMMUNOGOLD AND LECTIN-GOLD LABELING IN TUMOR RESEARCHAND DIAGNOSIS

Immunohistochemistry and carbohydrate histochemistry have had an enorm ous impact on both tumor research and diagnosis. In particular, immuno gold labeling has provided significant advantages over classical fluor escence and enzyme-based techniques. In light microscopy, the silver-i ntensified gold labeling has proven highly sensitive and precise in lo calization. In electron microscopy, the gold particle marker was a pre requisite for successful and unequivocal antigen detection in electron -dense cellular structures such as secretory granules. In this review we demonstrate the usefulness of light and electron microscopical gold labeling techniques as applied in tumor research and diagnosis. The e xamples include expression of beta-1,6 branches and specific sialoglyc oconjugates in colon carcinoma, b-12 carbohydrate epitope in breast ca rcinoma, polysialic acid in neuroendocrine tumors of lung, adrenal and thyroid, as well as studies on proinsulin to insulin conversion in in sulinomas. In addition, practical hints for prevention of background s taining, tissue fixation, and silver intensification of gold labeling are given.