Aquaporin-1 (AQP-1) expression in fluoro-edenite-induced mesothelioma effusions: an approach by cell-block procedure

Cytopathology 2018 June 6 [Link]

Angelico G, Ieni A, Caltabiano R, Zeppa P, Tuccari G


Aquaporin 1 (AQP-1) is a water channel protein found in cell membranes, whose expression has been considered an independent favourable prognostic factor in pleural Malignant Mesothelioma (MM). The aim of this study is to evaluate the expression of AQP-1 and its prognostic value in a series of pleural MM effusions, from a geographic area with high concentrations of Fluoro-Edenite (FE).
We selected twenty-five MM cases from Biancavilla (Italy), an area with high environmental concentrations of FE. Cytological samples, cell-blocks (CB), clinical and follow-up data were available for all cases. Immunohistochemistry (IHC) for calretinin, CK5/6, WT1, CK7 and TTF1 were used on CB sections to confirm the cytological diagnosis of MM. IHC for AQP-1 was performed and high expression was defined when ≥ 50% of tumour cells showed linear and circumferential membranous staining.
The cohort was composed of 16 men and 9 women (median age: 67,5 years; range: 49-88 years). The median survival was 14 months (range 1,5 to 60 months), with a significant value (p 0,006). All cases have been histologically confirmed and classified as epithelioid (16 cases), biphasic (7 cases) and sarcomatoid (2 cases). AQP-1 high expression has been observed in 16 cases. Comparing AQP-1 high expression to the survival of corresponding patients, a significant association with a slight increased overall survival (OS) of 12 months has been demonstrated. Nine patients with a AQP-1 score < 50% showed a shorter median OS (7 months). CONCLUSIONS: AQP-1 high expression is detectable on cytological samples of FE-induced MM with a prognostic value.