Defining a tumor as “homozygously deleted for CDKN2A” therefore requires defined cut-offs, such as 14.4% in a study by Wu et al. that compared the homozygous deletion patterns of CDKN2A between sarcomatoid mesothelioma and fibrous pleuritis [41]. The gene discussed is CDKN2A; the disease is sarcomatoid mesothelioma.