[Immunohistochemistry of soft tissue sarcoma].

The use of immunohistochemical procedures has been especially marked in the diagnosis of soft tissue sarcoma and such procedures have become widely used. The necessity of using immunohistochemical procedures as a diagnostic tool is thus increasing, but there are some problems and points that should be borne in mind, together with the attendant advantages, when making a practical immunohistochemical diagnosis. Selection of antibodies: It is important to make a careful check of a commercially available antibody in terms of the grade of antibody quality. Specificity of antibody: The pathologist should remember that proteins such as alpha-1-antitrypsin and S-100 protein are present not only in one type of cell but also in several other types. Since mast cells often present in soft tissue sarcoma frequently show positive findings, these findings should not be interpreted as a positive indication of the presence of tumor cells. Patients with negative findings should be diagnosed carefully. In the assessment of intermediate filaments, it is necessary to perform pretreatment with trypsin. There are limitations in differentiation from cancer and the evaluation of whether the lesion is benign or malignant. Since immunohistochemical procedures are very effective for diagnosing heterogeneous tumors (Triton tumor, etc.), they should be actively applied for this purpose.