Detection of serum amyloid A-derived proteins in formalin-fixed paraffin-embedded tissues: reliability of the method and expansion of its spectrum.

To further assess the reliability of the Shtrasburg method for detection of amyloid A in formalin-fixed, paraffin-embedded tissues and to expand the spectrum of the amyloid proteins analyzed by this method, we studied formalin-fixed, paraffin-embedded amyloid-containing tissues obtained from patients with the following types of amyloidosis: amyloid A, light chain, transthyretin, calcitonin, beta2 microglobulin, and senile seminal vesicle. The tissue samples were deparaffinized, processed, and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the Western blot technique. Only specimens from patients with amyloid A amyloidosis gave protein bands: a single 8.5-kd band in lanes of all tissues studied, except thyroid tissue, which displayed two bands of about 5 and 10 kd. Other types of amyloid failed to show any protein band. These findings suggest that the Shtrasburg method is sensitive, specific, and reliable and may have an important role in the diagnosis of amyloidosis.