Genomic and T cell repertoire biomarkers associated with malignant mesothelioma survival.

Background: Malignant mesothelioma (MM) is an exceedingly rare tumor with poor prognosis due to the limited availability of effective treatment. Immunotherapy has emerged as a novel treatment approach for MM, but less than 40% of the patients benefit from it. Thus, it is necessary to identify accurate and effective biomarkers that can predict the overall survival (OS) and immunotherapy efficacy for MM.

Methods: DNA sequencing was used to identify the genomic landscape based on the data from 86 Chinese patients. T cell receptor (TCR) sequencing was used to characterize MM TCR repertoires of 28 patients between October 2016 and April 2023.

Results: Patients with TP53, NF2, or CDKN2A variants at the genomic level, as well as those exhibiting lower Shannon index (<6.637), lower evenness (<0.028), or higher clonality (≥0.194) according to baseline tumor tissue TCR indexes, demonstrated poorer OS. Furthermore, patients with TP53, CDKN2A, or CDKN2B variants and those with a lower evenness (<0.030) in baseline tumor tissue showed worse immunotherapy efficacy. The present study is the first to identify five special TCR Vβ-Jβ rearrangements associated with MM immunotherapy efficacy.

Conclusions: The present study reported the largest-scale genomic landscape and TCR repertoire of MM in Chinese patients and identified genomic and TCR biomarkers for the prognosis and immunotherapy efficacy in MM. The study results might provide new insights for prospective MM trials using specific genes, TCR indexes, and TCR clones as biomarkers and offer a reference for future antitumor drugs based on TCR-specific clones.