UV-Induced Somatic Mutations Driving Clonal Evolution in Healthy Skin, Nevus, and Cutaneous Melanoma

Abstract

Introduction: Due to its aggressiveness, cutaneous melanoma (CM) is responsible for most skin cancer-related deaths worldwide. The origin of CM is closely linked to the appearance of UV-induced somatic mutations in melanocytes present in normal skin or in CM precursor lesions (nevi or dysplastic nevi). In recent years, new NGS studies performed on CM tissue have increased the understanding of the genetic somatic changes underlying melanomagenesis and CM tumor progression. Methods: We reviewed the literature using all important scientific databases. All articles related to genomic mutations in CM as well as normal skin and nevi were included, in particular those related to somatic mutations produced by UV radiation. Conclusions: CM development and progression are strongly associated with exposure to UV radiation, although each melanoma subtype has different characteristic genetic alterations and evolutionary trajectories. While BRAF and NRAS mutations are common in the early stages of tumor development for most CM subtypes, changes in CDKN2A, TP53 and PTEN, together with TERT promoter mutations, are especially common in advanced stages. Additionally, large genome duplications, loss of heterozygosity, and copy number variations are hallmarks of metastatic disease. Finally, the mutations driving melanoma targeted-therapy drug resistance are also summarized. The complete sequential stages of clonal evolution leading to CM onset from normal skin or nevi are still unknown, so further studies are needed in this field to shed light on the molecular pathways involved in CM malignant transformation and in melanoma acquired drug resistance.

Primary Undifferentiated/Dedifferentiated Cutaneous Melanomas—A Review on Histological, Immunohistochemical, and Molecular Features with Emphasis on Prognosis and Treatment

“…A total of 7 patients died of the disease on average 16.1 months after the diagnosis (median, 8; range 2-60) while 9 patients showed signs of progression (recurrence, nodal, and/or distant metastasis) on average 16.3 months after diagnosis (median, 12; range 3-42) and 7 patients showed no sign of progression after a mean follow up period of 20.7 months (median, 24; range 6-34). The deceased patients had a mean age of 70.5 (median, 72; range [64][65][66][67][68][69][70][71][72][73][74][75][76] and the maleto-female ratio was 3:4. The patients with progressive disease had a mean age of 62.2 (median 70 range 1-96) and the male-to-female ratio was 2:1.…”

Assessment of tumoral and peritumoral inflammatory reaction in cutaneous malignant melanomas

“…CM is a cancer with a lower incidence but a very high mortality rate. The CM origin is closely related to the presence and accumulation of UV-induced somatic mutations in melanocytes present in normal skin or in precursor lesions of CM (nevi or dysplastic nevi) [ 25 , 26 ]. Although these somatic mutations can be produced by accumulated, unrepaired, DNA errors related to cell aging, most studies showed that UV exposure is actually the main risk factor associated with the CM development [ 27 , 28 ].…”

Targeting CDK4/6 in glioblastoma via in situ injection of a cellulose-based hydrogel

“…Glioma stem cells (GSCs) constitute a self-renewing and slow-dividing sub-population within GBM. 25,26 They recapitulate the heterogeneity of their parent glioma tissues and show similarity in drug resistance and refraction to treatment to clinical GBM cases. As shown in Fig.…”