Alpha-methylacyl-CoA racemase is expressed in a majority of pancreatic neoplasms of neuroendocrine, acinar, and solid pseudopapillary differentiation.

Sir, Alpha-methylacyl-CoA racemase (AMACR) is an enzyme localised in peroxisomes and mitochondria, and involved in metabolism of branched chain fatty acids as well as some drugs. It is also a well recognised immunohistochemical (IHC) marker, particularly helpful in the diagnosis of limited prostatic adenocarcinoma. However, its usefulness in oncology and anatomical pathology practice may be much wider, as AMACR seems to be a good diagnostic and prognostic marker and, most importantly, a promising therapeutic target in many types of malignancies. Several groups of investigators showed that AMACR is expressed in a minor portion of ductal adenocarcinomas of the pancreas (7.7–12.5%). In contrast, data on AMACR expression status in other types of pancreatic neoplasms are limited. The aim of this study was to examine IHC expression of AMACR in non-ductal neoplasms of the pancreas: solid pseudopapillary neoplasms (SPN), neuroendocrine tumours (NET), neuroendocrine carcinomas (NEC), and acinar cell neoplasms (ACN, acinar cell carcinomas, mixed acinar-neuroendocrine carcinomas, and pancreatoblastomas). Although all of these pancreatic tumours are considerably less frequent than conventional ductal cancers, they may still be difficult to differentiate from each other and, in a proportion of cases, to cure. The tissue microarrays (TMAs) were prepared using formalin fixed, paraffin embedded tumour samples diagnosed using WHO reference book criteria. Fifty-seven tumour samples were included in the study: 12 cases of SPN, 29 cases of NET, seven cases of NEC, and nine cases of ACN (seven cases of acinar cell carcinoma, a single case of acinar-neuroendocrine carcinoma, and a single case of pancreatoblastoma). Details on clinicopathological characteristics of the study