Isabelle Opitz

CDKN2A deletion is a common alteration in pleural mesothelioma (PM) and frequently associated with co-deletion of MTAP. Since the standard detection method for CDKN2A deletion and FISH analysis is relatively expensive, we here investigated the suitability of inexpensive p16 and MTAP IHC by comparing concordance between IHC and OncoScan CNV arrays on samples from 52 PM patients. Concordance was determined using Cohen’s kappa statistics. Loss of CDKN2A was associated with co-deletion of MTAP in 71% of cases. CDKN2A-MTAP copy-number normal cases were also IHC positive in 93% of cases for p16 and 100% for MTAP, while homozygous deletion of CDKN2A-MTAP was always associated with negative IHC for both proteins. In cases with heterozygous CDKN2A-MTAP loss, IHC expression of p16 and MTAP was negative in 100% and 71%, respectively. MTAP and p16 IHC showed high sensitivity (MTAP 86.5%, p16 100%) and specificity (MTAP 100%, p16 93.3%) for the detection of any gene loss. Loss of MTAP expression occurred exclusively in conjunction with loss of p16 labeling. Both p16 and MTAP IHC showed high concordance with Oncoscan CNV arrays (kappa = 0.952, p < 0.0001, and kappa = 0.787, p < 0.0001 respectively). We recommend combined MTAP and p16 immunohistochemistry to confirm the diagnosis of PM.

This pilot study conducted in Switzerland aims to assess the implementation, execution, and performance of low-dose CT lung cancer screening (LDCT-LCS). With lung cancer being the leading cause of cancer-related deaths in Switzerland, the study seeks to explore the potential impact of screening on reducing mortality rates. However, initiating a lung cancer screening program poses challenges and depends on country-specific factors. This prospective study, initiated in October 2018, enrolled participants meeting the National Lung Cancer Study criteria or a lung cancer risk above 1.5% according to the PLCOm2012 lung cancer risk-model. LDCT scans were assessed using Lung-RADS. Enrollment and follow-up are ongoing. To date, we included 112 participants, with a median age of 62 years (IQR 57–67); 42% were female. The median number of packs smoked each year was 45 (IQR 38–57), and 24% had stopped smoking before enrollment. The mean PLCOm2012 was 3.7% (±2.5%). We diagnosed lung cancer in 3.6% of participants (95%, CI:1.0–12.1%), with various stages, all treated with curative intent. The recall rate for intermediate results (Lung-RADS 3,4a) was 15%. LDCT-LCS in Switzerland, using modified inclusion criteria, is feasible. Further analysis will inform the potential implementation of a comprehensive lung cancer screening program in Switzerland.

We previously demonstrated that cullin 4B (CUL4B) upregulation was associated with worse outcomes of pleural mesothelioma (PM) patients, while the overexpression of its paralog CUL4A was not associated with clinical outcomes. Here, we aimed to identify the distinct roles of CUL4B and CUL4A in PM using an siRNA approach in PM cell lines (ACC Meso-1 and Mero82) and primary culture. The knockdown of CUL4B and CUL4A resulted in significantly reduced colony formation, increased cell death, and delayed cell proliferation. Furthermore, similar to the effect of CUL4A knockdown, downregulation of CUL4B led to reduced expression of Hippo pathway genes including YAP1, CTGF, and survivin. Interestingly, CUL4B and not CUL4A knockdown reduced TGF-β1 and MMP2 expression, suggesting a unique association of CUL4B with this pathway. However, the treatment of PM cells with exogenous TGF-β1 following CUL4B knockdown did not rescue PM cell growth. We further analyzed ACC Meso-1 xenograft tumor tissues treated with the cullin inhibitor, pevonedistat, which targets protein neddylation, and observed the downregulation of human TGF-β1 and MMP2. In summary, our data suggest that CUL4B overexpression is important for tumor cell growth and survival and may drive PM aggressiveness via the regulation of TGF-β1 expression and, furthermore, reveal a new mechanism of action of pevonedistat.