Evaluation of Immunohistochemical Study of Maspin for Pancreatic Tumors Should Be Made in Caution: Immunohistochemical Studies and Quantitative Analysis of mRNA Using Materials from Endoscopic Ultrasound Guided-Fine Needle Aspiration
Katsuji Marukawa, Tomoko Mitsuhashi, Yoshihiro Matsuno. Hokkaido University Hospital, Sapporo, Hokkaido, Japan
Background: Differentiating pancreatic adenocarcinoma (AC) from atypical glands of non-neoplastic lesions using materials from endoscopic ultrasound guided-fine needle aspiration (EUS-FNA) is always challenging for pathologists. Maspin is known to have tumor-suppressor function and is expressed in certain kinds of adenocarcinomas, however; immunohistochemical localization of maspin has not been studied well.
Design: Fifty-three specimens obtained from EUS-FNA (45 ACs, 5 autoimmune pancreatitis (type 1), 1 inflammatory peudotumor and 2 normal pancreas) were studied. After confirming the existence of targeted cells by Papanicolaou stain, cover glasses were removed, cell transfer technique was applied to immunohistochemical (IHC) studies for maspin. In addition, quantitative analysis of mRNA (Real-time PCR) of maspin in 12 cases (9 ACs, 1 squamous cell carcinoma, 1 neuroendocrine tumor with normal acini, and 1 intraoperative peritoneal washing) was performed.
Results: Maspin is positive in 44 of 45 ACs (either nuclear or nuclear plus cytoplasmic) and 2 of 8 non-neoplastic lesions (sensitivity 95.6%, specificity 85.7%) by IHC studies. Among 12 cases subjected to quantitative analysis of mRNA of maspin, 9 of 10 carcinomas showed nuclear plus cytoplasmic IHC stains, and 1 of 10 showed only nuclear stains. Increased mRNA of maspin was observed in 8 of 9 cases showing nuclear plus cytoplasmic IHC stains. One AC case showing only nuclear stain did not have increased mRNA of maspin.
Conclusions: Sensitivity and specificity of maspin IHC using cell transfer technique were satisfactory. Although further studies are needed for the precise interpretation for IHC localization of maspin, only nuclear stain of maspin should be evaluated in caution for the diagnosis of malignancy according to the results of real-time PCR.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 131, Wednesday Afternoon