Endocrine Abstracts

Introduction

Insulinoma-associated-1 (INSM1), encoded by the INSM1 gene is key factor in pancreatic endocrine, sympatho-adrenal and pan-neurogenic development. It has also been identified in multiple tumors of neuroendocrine origin but not thoroughly investigated as a potential neoplastic biomarker. The aim of the study was to evaluated INSM1 as a semiquantitative immunohistochemical biomarker as well as quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) biomarker for pancreatic neuroendocrine tumors (PNETs).

Material and Methods

Metastatic PNETs (liver metastases) specimens (n = 24) matched control (normal) tissue were surgically collected and INSM1 expression for tumor and control tissue was analysed by immunohistochemistry. Additionally, mRNA expression was determined by qRT-PCR.

Results

INSM1 expression was significantly increased in neoplastic vs nonneoplastic tissue. Using immunohistrochemistry, we found that INSM1 was not detected in any control, nonneoplastic, non-neuroendocrine tissue. In PNETs tissue, INSM1 was detectable by immunohistochemistry and qRT-PCR in 22 of total 24 specimens (91.66%). Compared to normal tissue specimens, the INSM1 showed significant overexpression in metastatic PNETs.

Conclusion

Our findings highlight that INSM1 may serve as a promissing, novel, neuroendocrine, immunohistochemical and molecular biomarker in patient diagnosed with PNETs.