Spontaneous Mesotheliomas in Germline Bap1 Heterozygous Mice from Different Genetic Backgrounds

Area of Science:

• Oncology
• Genetics
• Toxicology

Background:

• Germline BAP1 mutations are linked to mesothelioma predisposition in humans.
• The role of BAP1 heterozygous mutations in spontaneous mesothelioma development in mice remains controversial.
• Bap1-mutant mice exhibit increased mesothelioma incidence with asbestos exposure.

Purpose of the Study:

• To investigate spontaneous mesothelioma development in a large cohort of Bap1-mutant and wild-type mice over their lifetimes.
• To statistically determine if Bap1 mutations alone significantly increase mesothelioma incidence.
• To assess the impact of genetic background on spontaneous mesothelioma development.

Main Methods:

• Lifetime monitoring of spontaneous mesothelioma in Bap1-mutant and wild-type mice across diverse genetic backgrounds.
• Statistical analysis using frequentist and Bayesian frameworks to compare mesothelioma incidence.
• Bayesian analysis incorporated historical data for WT mice using meta-analysis and predictive priors.

Main Results:

• Spontaneous mesotheliomas occurred in 2/329 Bap1-mutant mice and 0/227 wild-type mice.
• Four distinct statistical approaches found no significant difference in mesothelioma occurrence probability between mutant and wild-type mice.
• Results indicate no increased spontaneous mesothelioma risk solely due to germline Bap1 mutations.

Conclusions:

• Germline Bap1 mutations alone do not significantly increase the risk of spontaneous mesothelioma in mice.
• The study highlights the critical role of environmental factors, such as asbestos, in Bap1-associated mesothelioma.
• Further research may be needed to elucidate the precise mechanisms and thresholds for Bap1-driven carcinogenesis.