Complex communities of bacteria, fungi, and viruses thrive on our skin. The composition of these communities depends on skin characteristics, such as sebaceous gland concentration, moisture content, ...and temperature, as well as on host genetics and exogenous environmental factors. Recent metagenomic studies have uncovered a surprising diversity within these ecosystems and have fostered a new view of commensal organisms as playing a much larger role in immune modulation and epithelial health than previously expected. Understanding microbe-host interactions and discovering the factors that drive microbial colonization will help us understand the pathogenesis of skin diseases and develop new promicrobial and antimicrobial therapeutics.
Melanoma: from mutations to medicine Tsao, Hensin; Chin, Lynda; Garraway, Levi A ...
Genes & development,
2012-Jun-01, 2012-06-01, 20120601, Volume:
26, Issue:
11
Journal Article
Peer reviewed
Open access
Melanoma is often considered one of the most aggressive and treatment-resistant human cancers. It is a disease that, due to the presence of melanin pigment, was accurately diagnosed earlier than most ...other malignancies and that has been subjected to countless therapeutic strategies. Aside from early surgical resection, no therapeutic modality has been found to afford a high likelihood of curative outcome. However, discoveries reported in recent years have revealed a near avalanche of breakthroughs in the melanoma field-breakthroughs that span fundamental understanding of the molecular basis of the disease all the way to new therapeutic strategies that produce unquestionable clinical benefit. These discoveries have been born from the successful fruits of numerous researchers working in many-sometimes-related, although also distinct-biomedical disciplines. Discoveries of frequent mutations involving BRAF(V600E), developmental and oncogenic roles for the microphthalmia-associated transcription factor (MITF) pathway, clinical efficacy of BRAF-targeted small molecules, and emerging mechanisms underlying resistance to targeted therapeutics represent just a sample of the findings that have created a striking inflection in the quest for clinically meaningful progress in the melanoma field.
Genetics of melanocytic nevi Roh, Mi Ryung; Eliades, Philip; Gupta, Sameer ...
Pigment cell and melanoma research,
November 2015, Volume:
28, Issue:
6
Journal Article
Peer reviewed
Open access
Summary
Melanocytic nevi are a benign clonal proliferation of cells expressing the melanocytic phenotype, with heterogeneous clinical and molecular characteristics. In this review, we discuss the ...genetics of nevi by salient nevi subtypes: congenital melanocytic nevi, acquired melanocytic nevi, blue nevi, and Spitz nevi. While the molecular etiology of nevi has been less thoroughly studied than melanoma, it is clear that nevi and melanoma share common driver mutations. Acquired melanocytic nevi harbor oncogenic mutations in BRAF, which is the predominant oncogene associated with melanoma. Congenital melanocytic nevi and blue nevi frequently harbor NRAS mutations and GNAQ mutations, respectively, while Spitz and atypical Spitz tumors often exhibit HRAS and kinase rearrangements. These initial ‘driver’ mutations are thought to trigger the establishment of benign nevi. After this initial phase of the cell proliferation, a senescence program is executed, causing termination of nevi growth. Only upon the emergence of additional tumorigenic alterations, which may provide an escape from oncogene‐induced senescence, can malignant progression occur. Here, we review the current literature on the pathobiology and genetics of nevi in the hope that additional studies of nevi promise to inform our understanding of the transition from benign neoplasm to malignancy.
The incidence of primary cutaneous melanoma continues to increase each year. Melanoma accounts for the majority of skin cancer–related deaths, but treatment is usually curative following early ...detection of disease. In this American Academy of Dermatology clinical practice guideline, updated treatment recommendations are provided for patients with primary cutaneous melanoma (American Joint Committee on Cancer stages 0-IIC and pathologic stage III by virtue of a positive sentinel lymph node biopsy). Biopsy techniques for a lesion that is clinically suggestive of melanoma are reviewed, as are recommendations for the histopathologic interpretation of cutaneous melanoma. The use of laboratory, molecular, and imaging tests is examined in the initial work-up of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, recommendations for surgical margins and the concepts of staged excision (including Mohs micrographic surgery) and nonsurgical treatments for melanoma in situ, lentigo maligna type (including topical imiquimod and radiation therapy), are updated. The role of sentinel lymph node biopsy as a staging technique for cutaneous melanoma is described, with recommendations for its use in clinical practice. Finally, current data regarding pregnancy and melanoma, genetic testing for familial melanoma, and management of dermatologic toxicities related to novel targeted agents and immunotherapies for patients with advanced disease are summarized.
Despite the large body of mutational data available for melanoma and epidemiological studies linking this cancer to ultraviolet radiation (UVR), the fundamental carcinogenic mechanisms involved in ...melanoma remain largely unknown. To this end, we systematically reviewed, extracted, and analyzed mutational data from the extant melanoma literature in an effort to gain more insight into its early pathogenic events. We searched PubMed (1966–January 2006) using the words “mutation” AND “melanoma” in the title or . Out of 2,095 returned results, there were 203 eligible studies that were subsequently analyzed. We cataloged 8,201 somatic and cultured melanoma specimens and annotated 2,041 reported somatic sequence variants. The single BRAF c.1799T>A (p.Val600Glu) alteration is the most prevalent variant while other A:T>T:A transversions were uncommon. Four highly‐recurrent, non‐ultraviolet B (UVB) changes account for most of the NRAS and BRAF variants. CDKN2A, PTEN/MMAC1, and TP53 harbored statistically higher rates of UVB signature changes (64.2%, 52.4%, and 69.2%, respectively) than oncogenic loci (NRAS: 15.3% and BRAF: 2.4%). More specifically, cutaneous melanomas showed a significantly higher proportion of UVB signature mutations at both TP53 and CDKN2A when compared to non‐skin cancers using data from their respective locus‐specific databases. Superficial spreading and nodular melanomas had the highest rates of BRAF (53.4%) and NRAS (28.0%) mutations. In melanoma, there is sufficient mutational evidence to support a role for direct UVB participation, especially at TP53 and CDKN2A. For oncogenes, the role for UVB is less clear since functionally‐activating changes are uncommon and are subject to sequence constraints. Hum Mutat 28(6), 578–588, 2007. Published 2007 Wiley‐Liss, Inc.
Melanoma, originating from epidermal melanocytes, is a heterogeneous disease that has the highest mortality rate among all types of skin cancers. Numerous studies have revealed the cause of this ...cancer as related to various somatic driver mutations, including alterations in
KIT
—a proto-oncogene encoding for a transmembrane receptor tyrosine kinase. Although accounting for only 3% of all melanomas, mutations in c-KIT are mostly derived from acral, mucosal, and chronically sun-damaged melanomas. As an important factor for cell differentiation, proliferation, and survival, inhibition of c-KIT has been exploited for clinical trials in advanced melanoma. Here, apart from the molecular background of c-KIT and its cellular functions, we will review the wide distribution of alterations in
KIT
with a catalogue of more than 40 mutations reported in various articles and case studies. Additionally, we will summarize the association of
KIT
mutations with clinicopathologic features (age, sex, melanoma subtypes, anatomic location, etc.), and the differences of mutation rate among subgroups. Finally, several therapeutic trials of c-KIT inhibitors, including imatinib, dasatinib, nilotinib, and sunitinib, will be analyzed for their success rates and limitations in advanced melanoma treatment. These not only emphasize c-KIT as an attractive target for personalized melanoma therapy but also propose the requirement for additional investigational studies to develop novel therapeutic trials co-targeting c-KIT and other cytokines such as members of signaling pathways and immune systems.
Tumor mutational burden correlates with improved survival and immunotherapy response in some malignancies, and with tumor aggressiveness in others. To study the link between mutational burden and ...survival, we analyzed survival effects of tumor exonic missense mutation burden (TEMMB) across 6947 specimens spanning 31 cancers which have undergone whole exome sequencing as part of TCGA. We adjusted TEMMB for age, sex, stage, and recruitment center, and computed Cox-proportional models of TEMMB survival effects. We assigned a recurrence score (RS) to each cohort, defining RS as the burden of recurrent mutations exceeding 1% population prevalence. High TEMMB was associated with improved survival in cutaneous melanoma: hazard ratio (HR) = 0.71 0.60-0.85, p = 0.0002, urothelial bladder carcinoma: HR = 0.74 0.59-0.93, p = 0.01, and ovarian carcinoma: HR = 0.80 0.70-0.93, p = 0.003. High TEMMB was associated with decreased survival in colorectal adenocarcinoma: HR = 1.32 1.00-1.74, p < 0.05. We identified that TEMMB survival effects were governed by the balance of recurrent and non-recurrent mutations. In cancers with a low RS, high TEMMB was correlated with better survival outcomes (r = 0.49, p = 0.02). In conclusion, TEMMB effects on survival depend on recurrent mutation enrichment; tumor types that are highly enriched in passenger mutations show a survival benefit in the setting of high tumor mutational burden.
BAP1 has been shown to be a target of both somatic alteration in high-risk ocular melanomas (OM) and germline inactivation in a few individuals from cancer-prone families. These findings suggest that ...constitutional BAP1 changes may predispose individuals to metastatic OM and that familial permeation of deleterious alleles could delineate a new cancer syndrome.
To characterize BAP1's contribution to melanoma risk, we sequenced BAP1 in a set of 100 patients with OM, including 50 metastatic OM cases and 50 matched non-metastatic OM controls, and 200 individuals with cutaneous melanoma (CM) including 7 CM patients from CM-OM families and 193 CM patients from CM-non-OM kindreds.
Germline BAP1 mutations were detected in 4/50 patients with metastatic OM and 0/50 cases of non-metastatic OM (8% vs. 0%, p = 0.059). Since 2/4 of the BAP1 carriers reported a family history of CM, we analyzed 200 additional hereditary CM patients and found mutations in 2/7 CM probands from CM-OM families and 1/193 probands from CM-non-OM kindreds (29% vs. 0.52%, p = .003). Germline mutations co-segregated with both CM and OM phenotypes and were associated with the presence of unique nevoid melanomas and highly atypical nevoid melanoma-like melanocytic proliferations (NEMMPs). Interestingly, 7/14 germline variants identified to date reside in C-terminus suggesting that the BRCA1 binding domain is important in cancer predisposition.
Germline BAP1 mutations are associated with a more aggressive OM phenotype and a recurrent phenotypic complex of cutaneous/ocular melanoma, atypical melanocytic proliferations and other internal neoplasms (ie. COMMON syndrome), which could be a useful clinical marker for constitutive BAP1 inactivation.
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