Genomic analysis and clinical management of adolescent cutaneous melanoma

Melanoma in children: A systematic review and individual patient meta-analysis

The current evidence on paediatric melanoma is heterogeneous, especially regarding the prognosis of different histological subtypes. We sought to systematically review the evidence on paediatric melanoma, highlighting the major sources of heterogeneity and focusing on available data on single patients. A systematic search was performed from 1948 to 25 January 2021. Only studies reporting at least one case of cutaneous melanoma in patients aged ≤18 years were included. Unknown primary and uncertain malignant melanomas were excluded. Three couples of authors independently performed title/abstract screening and two different authors reviewed all the relevant full texts. The selected articles were manually cross-checked for overlapping data for qualitative synthesis. Subsequently data on single patients were extracted to perform a patient-level meta-analysis. PROSPERO registration number: CRD42021233248. The main outcomes were melanoma-specific survival (MSS) and progression-free survival (PFS) outcomes. Separate analyses were done of cases with complete information on histologic subtype, focusing on superficial spreading (SSM), nodular (NM) and spitzoid melanomas, as well as of those classified as de-novo (DNM) and acquired or congenital nevus-associated melanomas (NAM). The qualitative synthesis covered 266 studies; however, data on single patients were available from 213 studies including 1002 patients. Among histologic subtypes, NM had a lower MSS than both SSM and spitzoid melanoma, and a lower PFS than SSM. Spitzoid melanoma had a significantly higher progression risk than SSM and trended toward lower mortality. Focusing on nevus-associated status, DNM demonstrated better MSS after progression than congenital NAM, and no differences were highlighted in PFS. Our findings describe the existence of different biological patterns in paediatric melanoma. Specifically, spitzoid melanomas demonstrated intermediate behaviour between SSM and NM and showed a high risk of nodal progression but low mortality. This raises the question of whether spitzoid lesions are being over-diagnosed as melanoma in childhood.

Melanoma in children and adolescents: analysis of susceptibility genes in 123 Italian patients

BACKGROUND

A polygenic inheritance involving high, medium and low penetrance genes has been suggested for melanoma susceptibility in adults, but genetic information is scarce for paediatric patients.

OBJECTIVE

We aim to analyse the major high and intermediate melanoma risk genes, CDKN2A, CDK4, POT1, MITF and MC1R, in a large multicentre cohort of Italian children and adolescents in order to explore the genetic context of paediatric melanoma and to reveal potential differences in heritability between children and adolescents.

METHODS

One-hundred-twenty-three patients (<21 years) from nine Italian centres were analysed for the CDKN2A, CDK4, POT1, MITF, and MC1R melanoma predisposing genes. The rate of gene variants was compared between sporadic, familial and multiple melanoma patients and between children and adolescents, and their association with clinico-pathological characteristics was evaluated.

RESULTS

Most patients carried MC1R variants (67%), while CDKN2A pathogenic variants were found in 9% of the cases, the MITF E318K in 2% of patients and none carried CDK4 or the POT1 S270N pathogenic variant. Sporadic melanoma patients significantly differed from familial and multiple cases for the young age at diagnosis, infrequent red hair colour, low number of nevi, low frequency of CDKN2A pathogenic variants and of the MC1R R160W variant. Melanoma in children (≤12 years) had more frequently spitzoid histotype, were located on the head/neck and upper limbs and had higher Breslow thickness. The MC1R V92M variant was more common in children than in adolescents. CDKN2A common polymorphisms and MC1R variants were associated with a high number of nevi.

CONCLUSION

Our results confirm the scarce involvement of the major high-risk susceptibility genes in paediatric melanoma and suggest the implication of MC1R gene variants especially in the children population.

Behind the Scene: Exploiting MC1R in Skin Cancer Risk and Prevention

Melanoma and non-melanoma skin cancers (NMSCs) are the most frequent cancers of the skin in white populations. An increased risk in the development of skin cancers has been associated with the combination of several environmental factors (i.e., ultraviolet exposure) and genetic background, including melanocortin-1 receptor (MC1R) status. In the last few years, advances in the diagnosis of skin cancers provided a great impact on clinical practice. Despite these advances, NMSCs are still the most common malignancy in humans and melanoma still shows a rising incidence and a poor prognosis when diagnosed at an advanced stage. Efforts are required to underlie the genetic and clinical heterogeneity of melanoma and NMSCs, leading to an optimization of the management of affected patients. The clinical implications of the impact of germline MC1R variants in melanoma and NMSCs' risk, together with the additional risk conferred by somatic mutations in other peculiar genes, as well as the role of MC1R screening in skin cancers' prevention will be addressed in the current review.

The Emerging Role of Ras Pathway Signaling in Pediatric Cancer

As genomic sequencing has become more widely available, the high prevalence of Ras pathway mutations in pediatric diseases has begun to emerge. Germline Ras-activating mutations have been known to contribute to cancer predisposition in a group of disorders known as the RASopathies, and now large pediatric sequencing studies have identified frequent somatic Ras pathway alterations across a diverse group of pediatric malignancies. These include glial brain tumors, relapsed high-risk neuroblastoma, embryonal rhabdomyosarcoma, acute myeloid leukemia, and relapsed acute lymphoblastic leukemia, and their prognostic impact is becoming increasingly better understood. Clinically, there has been success in targeting the Ras pathway in pediatric diseases, including the use of MEK inhibitors in plexiform neurofibromas associated with neurofibromatosis type 1 and the use of Ras pathway inhibitors in low-grade gliomas. Given the importance of this pathway in pediatric cancer, it is imperative that future studies strive to better understand the functional significance of these mutations, including their role in tumor growth and treatment resistance and how they can be better targeted to improve outcomes.

Targeting RAS in pediatric cancer: is it becoming a reality?

PURPOSE OF REVIEW

The current review aims to highlight the frequency of RAS mutations in pediatric leukemias and solid tumors and to propose strategies for targeting oncogenic RAS in pediatric cancers.

RECENT FINDINGS

The three RAS genes (HRAS, NRAS, and KRAS) comprise the most frequently mutated oncogene family in human cancer. RAS mutations are commonly observed in three of the leading causes of cancer death in the United States, namely lung cancer, pancreatic cancer, and colorectal cancer. The association of RAS mutations with these aggressive malignancies inspired the creation of the National Cancer Institute RAS initiative and spurred intense efforts to develop strategies to inhibit oncogenic RAS, with much recent success. RAS mutations are frequently observed in pediatric cancers; however, recent advances in anti-RAS drug development have yet to translate into pediatric clinical trials.

SUMMARY

We find that RAS is mutated in common and rare pediatric malignancies and that oncogenic RAS confers a functional dependency in these cancers. Many strategies for targeting RAS are being pursued for malignancies that primarily affect adults and there is a clear need for inclusion of pediatric patients in clinical trials of these agents.

Paediatric melanoma: clinical update, genetic basis, and advances in diagnosis

Paediatric melanoma is rare and challenging to diagnose. The three subtypes are Spitzoid melanoma, melanoma arising in a congenital melanocytic nevus, and conventional (also known as adult-type) melanoma. Spitzoid melanomas have characteristic histopathological and genomic aberrations. Despite frequent involvement of the sentinel lymph nodes, most cases have an uneventful clinical course. Among congenital nevi, the risk of melanoma varies by projected size in adulthood, with the greatest risk in large or giant nevi. The clinical course is generally aggressive and accounts for most melanoma-related deaths in childhood. In conventional melanoma, superficial spreading and nodular melanoma account for most cases, with risk factors and presentation largely similar to adult disease. In this Review, we discuss advances in histological diagnosis using adjunctive molecular assays, and summarise the genetic basis of paediatric melanoma.

MC1R variants in childhood and adolescent melanoma: a retrospective pooled analysis of a multicentre cohort

BACKGROUND

Germline variants in the melanocortin 1 receptor gene (MC1R) might increase the risk of childhood and adolescent melanoma, but a clear conclusion is challenging because of the low number of studies and cases. We assessed the association of MC1R variants with childhood and adolescent melanoma in a large study comparing the prevalence of MC1R variants in child or adolescent patients with melanoma to that in adult patients with melanoma and in healthy adult controls.

METHODS

In this retrospective pooled analysis, we used the M-SKIP Project, the Italian Melanoma Intergroup, and other European groups (with participants from Australia, Canada, France, Greece, Italy, the Netherlands, Serbia, Spain, Sweden, Turkey, and the USA) to assemble an international multicentre cohort. We gathered phenotypic and genetic data from children or adolescents diagnosed with sporadic single-primary cutaneous melanoma at age 20 years or younger, adult patients with sporadic single-primary cutaneous melanoma diagnosed at age 35 years or older, and healthy adult individuals as controls. We calculated odds ratios (ORs) for childhood and adolescent melanoma associated with MC1R variants by multivariable logistic regression. Subgroup analysis was done for children aged 18 or younger and 14 years or younger.

FINDINGS

We analysed data from 233 young patients, 932 adult patients, and 932 healthy adult controls. Children and adolescents had higher odds of carrying MC1R r variants than did adult patients (OR 1·54, 95% CI 1·02-2·33), including when analysis was restricted to patients aged 18 years or younger (1·80, 1·06-3·07). All investigated variants, except Arg160Trp, tended, to varying degrees, to have higher frequencies in young patients than in adult patients, with significantly higher frequencies found for Val60Leu (OR 1·60, 95% CI 1·05-2·44; p=0·04) and Asp294His (2·15, 1·05-4·40; p=0·04). Compared with those of healthy controls, young patients with melanoma had significantly higher frequencies of any MC1R variants.

INTERPRETATION

Our pooled analysis of MC1R genetic data of young patients with melanoma showed that MC1R r variants were more prevalent in childhood and adolescent melanoma than in adult melanoma, especially in patients aged 18 years or younger. Our findings support the role of MC1R in childhood and adolescent melanoma susceptibility, with a potential clinical relevance for developing early melanoma detection and preventive strategies.

FUNDING

SPD-Pilot/Project-Award-2015; AIRC-MFAG-11831.

TNF-alpha and metalloproteases as key players in melanoma cells aggressiveness

Background

Melanoma aggressiveness determines its growth and metastatic potential. This study aimed at identifying new molecular pathways controlling melanoma cell malignancy.

Methods

Ten metastatic melanoma cell lines were characterized by their proliferation, migration and invasion capabilities. The most representative cells were also characterized by spheroid formation assay, gene- and protein- expression profiling as well as cytokines secretion and the most relevant pathways identified through bioinformatic analysis were tested by in silico transcriptomic validation on datasets generated from biopsies specimens of melanoma patients. Further, matrix metalloproteases (MMPs) activity was tested by zymography assays and TNF-alpha role was validated by anti-TNF cell-treatment.

Results

An aggressiveness score (here named Melanoma AGgressiveness Score: MAGS) was calculated by measuring proliferation, migration, invasion and cell-doubling time in10human melanoma cell lines which were clustered in two distinct groups, according to the corresponding MAGS. SK-MEL-28 and A375 cell lines were selected as representative models for the less and the most aggressive phenotype, respectively. Gene-expression and protein expression data were collected for SK-MEL-28 and A375 cells by Illumina-, multiplex x-MAP-and mass-spectrometry technology. The collected data were subjected to an integrated Ingenuity Pathway Analysis, which highlighted that cytokine/chemokine secretion, as well as Cell-To-Cell Signaling and Interaction functions as well as matrix metalloproteases activity were significantly different in these two cell types. The key role of these pathways was then confirmed by functional validation. TNF role was confirmed by exposing cells to the anti-TNF Infliximab antibody. Upon such treatment melanoma cells aggressiveness was strongly reduced. Metalloproteases activity was assayed, and their role was confirmed by comparing transcriptomic data from cutaneous melanoma patients (n = 45) and benign nevi (n = 18).

Conclusions

Inflammatory signals such as TNF and MMP-2 activity are key intrinsic players to determine melanoma cells aggressiveness suggesting new venue sin the identification of novel molecular targets with potential therapeutic relevance.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0982-1) contains supplementary material, which is available to authorized users.

Pediatric melanoma in melanoma-prone families

BACKGROUND

In the United States, only approximately 0.4% of all melanomas are diagnosed in patients aged <20 years. To the authors' knowledge, melanoma in pediatric members of melanoma-prone families has not been fully investigated to date. The objective of the current study was to evaluate pediatric patients with melanoma with extensive follow-up in melanoma-prone families with and without cyclin-dependent kinase inhibitor 2A (CDKN2A) mutations.

METHODS

For this non-population-based study, families were followed prospectively for up to 40 years. A total of 60 families with ≥ 3 patients with melanoma were included for analysis: 30 CDKN2A mutation-positive (CDKN2A+) and 30 CDKN2A mutation-negative (CDKN2A-) families. Age at the time of first melanoma and number of melanomas were obtained for each patient and summarized by family or sets (CDKN2A + vs CDKN2A-). For set comparisons and categorical variables (occurrence of melanoma in pediatric patients, number of melanomas, number of patients with single or multiple melanomas), the Pearson chi-square or Fisher exact test was used.

RESULTS

Regardless of CDKN2A status, melanoma-prone families were found to have 6-fold to 28-fold higher percentages of patients with pediatric melanoma compared with the general population of patients with melanoma in the United States. Within CDKN2A + families, pediatric patients with melanoma were significantly more likely to have multiple melanomas compared with their relatives who were diagnosed at age >20 years (71% vs 38%, respectively; P = .004). CDKN2A + families had significantly higher percentages of pediatric patients with melanoma compared with CDKN2A- families (11.1% vs 2.5%; P = .004).

CONCLUSIONS

These observations have implications for the prevention of melanoma as well as clinical care for its early detection. Children in melanoma-prone families should have careful sun protection from an early age and skin surveillance to reduce their risk of melanoma.

Clinical and dermoscopic characterization of pediatric and adolescent melanomas: Multicenter study of 52 cases

BACKGROUND

Knowledge regarding the morphologic spectrum of pediatric melanoma (PM) is sparse, and this may in part contribute to delay in detection and thicker tumors.

OBJECTIVE

To analyze the clinicodermoscopic characteristics of PM.

METHODS

Retrospective study of 52 melanomas diagnosed in patients before the age of 20 years.

RESULTS

On the basis of its clinical, dermoscopic, and histopathologic characteristics, PM can be classified as spitzoid or nonspitzoid. The nonspitzoid melanomas (n = 37 [72.3%]) presented in patients with a mean age of 16.3 years (range, 8-20) and were associated with a high-risk phenotype and a pre-existing nevus (62.2%). The spitzoid melanomas (n = 15 [27.7%]) were diagnosed in patients at a mean age of 12.5 years (range, 2-19) and were mostly de novo lesions (73.3%) located on the limbs (73.3%). Whereas less than 25% of PMs fulfilled the modified clinical ABCD criteria (amelanotic, bleeding bump, color uniformity, de novo at any diameter), 40% of spitzoid melanomas did. Dermoscopic melanoma criteria were found in all cases. Nonspitzoid melanomas tended to be multicomponent (58.3%) or have nevus-like (25%) dermoscopic patterns. Spitzoid melanomas revealed atypical vascular patterns with shiny white lines (46.2%) or an atypical pigmented spitzoid pattern (30.8%). There was good correlation between spitzoid subtype histopathologically and dermoscopically (κ = 0.66).

LIMITATIONS

A retrospective study without re-review of pathologic findings.

CONCLUSION

Dermoscopy in addition to conventional and modified clinical ABCD criteria helps in detecting PM. Dermoscopy assists in differentiating spitzoid from nonspitzoid melanomas.