Is Islet Amyloid Polypeptide indeed expressed in the human brain?

There was no specific expression of IAPP in human brain tissue; hence an association between IAPP and ADNC is not assessable. Of note, the observed reactivity of the polyclonal IAPP Ab was not reproduced with a specific monoclonal Ab, thus we considered the observed staining with the polyclonal Ab to be unreliable. When using IHC, several pitfalls, especially the choice of an Ab, always need to be considered. Polyclonal Abs cross-react with other epitopes and proteins, thus leading to false-positive results. This seems to be the case for the polyclonal IAPP Abs in the human brain.