Multiplatform Analysis of Intratumoral PTEN Heterogeneity in Melanoma.
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ABSTRACT: Loss of protein expression of the tumor suppressor PTEN is associated with increased cancer aggressiveness, decreased tumor immune infiltration, and resistance to immune and targeted therapies in melanoma. We assessed a unique cohort of eight melanoma samples with focal loss of PTEN protein expression to understand the features and mechanisms of PTEN loss in this disease. We compared the PTEN-negative (PTEN[-]) areas to their adjacent PTEN-positive (PTEN[+]) areas using DNA sequencing, DNA methylation, RNA expression, digital spatial profiling, and immunohistochemical platforms. Variations or homozygous deletions of PTEN were identified in PTEN(-) areas that were not detected in the adjacent PTEN(+) areas in three cases (37.5%), but no clear genomic or DNA methylation basis for loss was identified in the remaining PTEN(-) samples. RNA expression data from two independent platforms identified a consistent increase in chromosome segregation gene expression in PTEN(-) versus adjacent PTEN(+) areas. Proteomic analysis showed a relative paucity of tumor-infiltrating lymphocytes in PTEN(-) versus adjacent PTEN(+) areas. The findings add to our understanding of potential molecular intratumoral heterogeneity in melanoma and the features associated with the loss of PTEN protein in this disease.
SUBMITTER: Chagani S
PROVIDER: S-EPMC10475489 | biostudies-literature | 2023 Sep
REPOSITORIES: biostudies-literature
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