[Immunohistochemical diagnosis by means of tyramide signal amplification]

Immunohistochemistry is used for in situ detection of proteins in histological slides and is now an important diagnostic tool. Due to several methodological and biological factors, conventional immunohistochemical procedures may sometimes have too low sensitivity, especially for tracing the histogenesis of malignant tumours. A few years ago, an amplification technique was introduced which greatly increased the sensitivity of some of the commonly used immunohistochemical methods. This technique permits the use of primary antibodies in significantly lower concentrations compared with the conventional methods. Alternatively, one can keep the antibody concentration unchanged and use the enhanced sensitivity to detect scarce proteins, which are not visualised by traditional immunohistochemical procedures. We present a brief description of the technique and show some examples of its use in the diagnosis of neuroendocrine carcinomas. Tyramide signal amplification might become an important supplement for the diagnosis and classification of malignant tumours.