Homozygous deletion of CDKN2A in malignant mesothelioma: Diagnostic utility, patient characteristics and survival in a UK mesothelioma centre

•This is the largest study of p16 FISH testing in real-world practice (n = 216).•60 % of mesotheliomas harboured a homozygous deletion of CDKN2A.•There were no false positive results using a cut-off of >20 % cells displaying CDKN2A deletion.•The highest proportion of cells with CDKN2A deletion in benign pleuritis was 13 %.•P16 FISH expands the diagnostic reach in cases of suspected but not definitive mesothelioma.