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The diagnostic value of immunohistochemically detected methylthioadenosine phosphorylase deficiency in malignant pleural mesotheliomas
Author(s) -
Zimling Zarah Glad,
Jørgensen Anne,
SantoniRugiu Eric
Publication year - 2012
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2012.04196.x
Subject(s) - medicine , immunohistochemistry , pathology , mesothelioma , cohort , histopathology , staining , gastroenterology
Zimling Z G, Jørgensen A & Santoni‐Rugiu E (2012) Histopathology 60, E96–E105 The diagnostic value of immunohistochemically detected methylthioadenosine phosphorylase deficiency in malignant pleural mesotheliomas Aims: Malignant pleural mesothelioma (MPM) often causes diagnostic difficulties for pathologists. We assessed whether loss of methylthioadenosine phosphorylase (MTAP), a key enzyme in the intracellular recycling of adenosine triphosphate (ATP) often deleted in MPM, could be detected with immunohistochemistry (IHC) and used as a diagnostic marker for MPM. Methods and results: We used IHC to detect MTAP in a cohort of 99 MPMs and 39 reactive mesothelial proliferations (RP) (reactive mesothelial hyperplasia n = 33, reactive pleural fibrosis n = 6). MTAP staining was assessed by an H score. The median H score of the RP cohort was set as a reference point. Cases with H scores below this reference point were considered to have decreased MTAP expression. We found that 64 of 99 (65%) of the investigated MPMs had decreased MTAP expression, while this was only true for nine of 39 (23%) of the RPs ( P = 0.001). We further evaluated MTAP expression in a cohort of coagulated pleural effusions from 14 patients with MPM and 20 patients with RP by using a double‐staining technique with Wilms tumour 1 (WT1) as a mesothelial marker. In these samples, decreased MTAP expression diagnosed MPM with a sensitivity of 71% and a specificity of 90%. Conclusions: Decreased MTAP expression could potentially be useful in combination with other markers in the diagnosis of MPM.