Aquaporin‐1 expression in fluoro‐edenite‐induced mesothelioma effusions: An approach by cell‐block procedure

摘要

Abstract Objective 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 was to evaluate the expression of AQP ‐1 and its prognostic value in a series of pleural MM effusions, from a geographical area with high concentrations of fluoro‐edenite ( FE ). Methods We selected 25 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 for calretinin, CK 5/6, WT 1, CK 7 and TTF 1 was used on CB sections to confirm the cytological diagnosis of MM . Immunohistochemistry for AQP ‐1 was performed and high expression was defined when ≥50% of tumour cells showed linear and circumferential membranous staining. Results The cohort included 16 men and nine women (median age: 67.5?years; range: 49‐88?years). The median survival was 14?months (range 1.5‐60?months), with a significant value ( P = 0.006). All cases have been histologically confirmed and classified as epithelioid (16 cases), biphasic (seven cases) and sarcomatoid (two 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 of 12?months has been demonstrated. Nine patients with a AQP ‐1 score less than 50% showed a shorter median overall survival (7?months). Conclusions AQP ‐1 high expression is detectable on cytological samples of FE ‐induced MM with a prognostic value.