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Miranda C.,Molecular Mechanisms Unit | Mazzoni M.,Molecular Mechanisms Unit | Sensi M.,Immunobiology of Human Tumors Unit | Pierotti M.A.,Scientific Directorate | Greco A.,Molecular Mechanisms Unit
Genes Chromosomes and Cancer | Year: 2014

Cutaneous melanoma is the most aggressive form of skin cancer, with a complex and heterogeneous aetiology. Deregulation of the mitogen activated protein kinase cascade is common in melanoma, due to activating mutations in the BRAF and NRAS genes. Genetic studies and high-throughput screening technologies have recently identified several somatic mutations affecting different receptor tyrosine kinase (RTK) genes. For the majority of these, however, the contribution to the complexity of melanoma biology has not been assessed. Among these, two novel missense somatic mutations (M379I and R577G) have recently been identified in the gene encoding the neurotrophic RTK NTRK1. The NTRK1 melanoma-associated point mutations were introduced in a NTRK1 expression plasmid. Functional characterization of mutants was assessed after transient and stable transfection in HeLa and NIH3T3 cells, respectively. We showed that M379I and R577G NTRK1 receptors do not display the kinase as constitutively activated and are functionally indistinguishable from the wild-type NTRK1 receptor. Our results indicate that a causative role for M379I and R577G NTRK1 mutations in melanoma development is highly unlikely. This supports the issue that, in parallel to systematic large scale cancer genome screening, functional studies are required to distinguish between mutations that play a causative role in tumor development and others that may only be passenger changes. © 2014 Wiley Periodicals, Inc. Source


Vallacchi V.,Immunotherapy Unit | Vergani E.,Immunotherapy Unit | Camisaschi C.,Immunotherapy Unit | Deho P.,Immunotherapy Unit | And 18 more authors.
Cancer Research | Year: 2014

Sentinel lymph nodes set the stance of the immune system to a localized tumor and are often the first site to be colonized by neoplastic cells that metastasize. To investigate how the presence of neoplastic cells in sentinel lymph nodes may trigger pathways associated with metastatic progression, we analyzed the transcriptional profiles of archival sentinel node biopsy specimens obtained from melanoma patients. Biopsies from positive nodes were selected for comparable tumor infiltration, presence or absence of further regional node metastases, and relapse at 5-year follow-up. Unsupervised analysis of gene expression profiles revealed immune response to be a major gene ontogeny represented. Among genes upregulated in patients with progressing disease, the TNF receptor family member CD30/TNFRSF8 was confirmed in biopsy specimens from an independent group of patients. Immunohistochemical analysis revealed higher numbers of CD30+ lymphocytes in nodes from progressing patients compared with nonprogressing patients. Phenotypic profiling demonstrated that CD30+ lymphocytes comprised a broad population of suppressive or exhausted immune cells, such as CD4+Foxp3+ or PD1 + subpopulations and CD4-CD8- T cells. CD30+ T lymphocytes were increased in peripheral blood lymphocytes of melanoma patients at advanced disease stages. Our findings reinforce the concept that sentinel nodes act as pivotal sites for determining progression patterns, revealing that the presence of CD30+ lymphocytes at those sites associate positively with melanoma progression. © 2014 American Association for Cancer Research. Source

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