Real-world EGFR testing practices for non-small-cell lung cancer by thoracic pathology laboratories across Europe

BACKGROUND

Testing for epidermal growth factor receptor (EGFR) mutations is an essential recommendation in guidelines for metastatic non-squamous non-small-cell lung cancer, and is considered mandatory in European countries. However, in practice, challenges are often faced when carrying out routine biomarker testing, including access to testing, inadequate tissue samples and long turnaround times (TATs).

MATERIALS AND METHODS

To evaluate the real-world EGFR testing practices of European pathology laboratories, an online survey was set up and validated by the Pulmonary Pathology Working Group of the European Society of Pathology and distributed to 64 expert testing laboratories. The retrospective survey focussed on laboratory organisation and daily EGFR testing practice of pathologists and molecular biologists between 2018 and 2021.

RESULTS

TATs varied greatly both between and within countries. These discrepancies may be partly due to reflex testing practices, as 20.8% of laboratories carried out EGFR testing only at the request of the clinician. Many laboratories across Europe still favour single-test sequencing as a primary method of EGFR mutation identification; 32.7% indicated that they only used targeted techniques and 45.1% used single-gene testing followed by next-generation sequencing (NGS), depending on the case. Reported testing rates were consistent over time with no significant decrease in the number of EGFR tests carried out in 2020, despite the increased pressure faced by testing facilities during the COVID-19 pandemic. ISO 15189 accreditation was reported by 42.0% of molecular biology laboratories for single-test sequencing, and by 42.3% for NGS. 92.5% of laboratories indicated they regularly participate in an external quality assessment scheme.

CONCLUSIONS

These results highlight the strong heterogeneity of EGFR testing that still occurs within thoracic pathology and molecular biology laboratories across Europe. Even among expert testing facilities there is variability in testing capabilities, TAT, reflex testing practice and laboratory accreditation, stressing the need to harmonise reimbursement technologies and decision-making algorithms in Europe.

Multiomic analysis of malignant pleural mesothelioma identifies molecular axes and specialized tumor profiles driving intertumor heterogeneity

Malignant pleural mesothelioma (MPM) is an aggressive cancer with rising incidence and challenging clinical management. Through a large series of whole-genome sequencing data, integrated with transcriptomic and epigenomic data using multiomics factor analysis, we demonstrate that the current World Health Organization classification only accounts for up to 10% of interpatient molecular differences. Instead, the MESOMICS project paves the way for a morphomolecular classification of MPM based on four dimensions: ploidy, tumor cell morphology, adaptive immune response and CpG island methylator profile. We show that these four dimensions are complementary, capture major interpatient molecular differences and are delimited by extreme phenotypes that-in the case of the interdependent tumor cell morphology and adapted immune response-reflect tumor specialization. These findings unearth the interplay between MPM functional biology and its genomic history, and provide insights into the variations observed in the clinical behavior of patients with MPM.

[Lung involvement of pyoderma gangrenosum: Diagnostic and therapeutic discussion based on a case report and a targeted literature review]

INTRODUCTION

Pyoderma gangrenosum (PG) is a rare, mainly dermatological condition, whose unusual and little-known lung involvement presents a diagnostic and therapeutic challenge.

CASE REPORT

A 66-year-old man, followed for 6 years for an IgA monoclonal gammopathy of undetermined significance and an initially cutaneous corticosteroid-dependent PG, received a pneumonectomy for a mass suspected of neoplasia, that turns out to be a PG pulmonary localisation. During successive pneumopathies, sometimes dyspneic and excavated, several hypotheses are discussed. Various infectious and immunological explorations, and various antibacterial/fungal or immunosuppressive therapies are conducted, to finally conclude to pulmonary and/or cutaneous recurrences of PG. The outcome at 14 months seems finally favourable with tofacitinib.

CONCLUSION

The recognition of cutaneous involvement of PG, which is essential for the diagnosis of its lung involvement, is probably the mirror of its evolution under treatment. Only multidisciplinary confrontation of reported cases will allow the elaboration of diagnostic and therapeutic recommendations.

Comprehensive Molecular and Pathologic Evaluation of Transitional Mesothelioma Assisted by Deep Learning Approach: A Multi-Institutional Study of the International Mesothelioma Panel from the MESOPATH Reference Center

INTRODUCTION

Histologic subtypes of malignant pleural mesothelioma are a major prognostic indicator and decision denominator for all therapeutic strategies. In an ambiguous case, a rare transitional mesothelioma (TM) pattern may be diagnosed by pathologists either as epithelioid mesothelioma (EM), biphasic mesothelioma (BM), or sarcomatoid mesothelioma (SM). This study aimed to better characterize the TM subtype from a histological, immunohistochemical, and molecular standpoint. Deep learning of pathologic slides was applied to this cohort.

METHODS

A random selection of 49 representative digitalized sections from surgical biopsies of TM was reviewed by 16 panelists. We evaluated BAP1 expression and CDKN2A (p16) homozygous deletion. We conducted a comprehensive, integrated, transcriptomic analysis. An unsupervised deep learning algorithm was trained to classify tumors.

RESULTS

The 16 panelists recorded 784 diagnoses on the 49 cases. Even though a Kappa value of 0.42 is moderate, the presence of a TM component was diagnosed in 51%. In 49% of the histological evaluation, the reviewers classified the lesion as EM in 53%, SM in 33%, or BM in 14%. Median survival was 6.7 months. Loss of BAP1 observed in 44% was less frequent in TM than in EM and BM. p16 homozygous deletion was higher in TM (73%), followed by BM (63%) and SM (46%). RNA sequencing unsupervised clustering analysis revealed that TM grouped together and were closer to SM than to EM. Deep learning analysis achieved 94% accuracy for TM identification.

CONCLUSION

These results revealed that the TM pattern should be classified as non-EM or at minimum as a subgroup of the SM type.

Intra-Alveolar Haemorrhage Complicating IgA Vasculitis: A Case Report, Literature Review and Discussion of Treatment

Introduction

Immunoglobulin A vasculitis (IgAV) is a small-vessel vasculitis with IgA-dominant immune deposits. IgAV frequently involves the skin, gastrointestinal tract, joints and kidneys. In contrast to other types of small-vessel vasculitis, IgAV is rarely complicated by intra-alveolar haemorrhage (IAH).

Methods/Results

We describe a patient with relapsing bladder cancer who presented with IAH during the course of IgAV successfully treated with corticosteroids alone.

Conclusion

This case report reminds us that IgAV can manifest with IAH. There are no robust data to support the systematic use of cyclophosphamide or plasma exchange as first-line therapy for IgAV with IAH.

LEARNING POINTS