Cutaneous melanoma primary site is linked to nevus density

Mutational Characterization of Cutaneous Melanoma Supports Divergent Pathways Model for Melanoma Development

According to the divergent pathway model, cutaneous melanoma comprises a nevogenic group with a propensity to melanocyte proliferation and another one associated with cumulative solar damage (CSD). While characterized clinically and epidemiologically, the differences in the molecular profiles between the groups have remained primarily uninvestigated. This study has used a custom gene panel and bioinformatics tools to investigate the potential molecular differences in a thoroughly characterized cohort of 119 melanoma patients belonging to nevogenic and CSD groups. We found that the nevogenic melanomas had a restricted set of mutations, with the prominently mutated gene being BRAF. The CSD melanomas, in contrast, showed mutations in a diverse group of genes that included NF1, ROS1, GNA11, and RAC1. We thus provide evidence that nevogenic and CSD melanomas constitute different biological entities and highlight the need to explore new targeted therapies.

Solar Ultraviolet Exposure in Individuals Who Perform Outdoor Sport Activities

BACKGROUND

Skin cancer is the most common cancer in the USA. Therefore, it is important to review the contribution of ultraviolet radiation (UVR) exposure to skin cancer in individuals with the highest risk. Documenting the relationship between outdoor sports solar ultraviolet exposure and their risk of skin cancer along with appropriate risk mitigation strategies can help inform clinicians of practical information for counseling sun protective behaviors in this population.

METHODS

We conducted a review of the current evidence using PubMed to answer the following research questions: (1) How is ultraviolet radiation measured? (2) What is the modern utility of the ultraviolet index in modifying recreational sun protection behaviors? (3) What is the risk of developing skin cancer for outdoor sport participants? (4) What is the prevalence of skin cancer in sport participants? and (5) Is the number of nevi and solar lentigines elevated in outdoor sport participants?

RESULTS

Based on the literature, individuals who practice outdoor sport-related activities receive high ultraviolet radiation exposure, have a high risk for skin cancer, have a high prevalence for pigmented lesions, and may benefit from electronic sun protection educational interventions.

CONCLUSIONS

Individuals who practice outdoor sports experience substantially higher ultraviolet radiation exposure, routinely exceed the recommended exposure limits, and are at a higher risk of developing skin cancer. Therefore, those who are frequently engaged in outdoor leisure activities should be coached about efficient sun protective practices and relevant mobile technologies that may facilitate adherence.

Mutations in the BRAF, NRAS, and C-KIT Genes of Patients Diagnosed with Melanoma in Colombia Population

INTRODUCTION

Mutations in the BRAF, NRAS, and C-KIT genes have been associated with the histopathological characteristics of melanoma. Likewise, the incidence of each of these subtypes changes according to the geographical origin of the population analyzed.

OBJECTIVE

To determine the mutation frequency in exons 11 and 15 of the BRAF gene, exons 1 and 2 of the NRAS gene, and exons 11, 13, and 17 of the C-KIT gene and to relate it with histological subtypes in patients from a region with high levels of ultraviolet radiation. Methodology. The clinicopathological characteristics of 54 cutaneous melanoma samples were analyzed. Mutation analysis was performed via qPCR on paraffin-embedded tumor tissue samples using probes specific for the V600E mutation. Amplification of exons 11 and 15 of the BRAF gene, exons 1 and 2 of the NRAS gene, and exons 11, 13, and 17 of the C-KIT gene was performed for subsequent sequencing using the Sanger method.

RESULT

The most frequent histological subtype in the analyzed sample was lentigo maligna/lentigo maligna melanoma (52%) followed by acral lentiginous melanoma (20%). The BRAF-V600 variant was the most frequent (63.6%). The most frequent (54%) mutation in NRAS was p.Lys5∗. In the C-KIT gene, only the Val560Ala mutation was found.

CONCLUSION

Differences in histological subtypes and mutations in the BRAF, NRAS, and C-KIT genes were found in the analyzed population. This indicates that environmental and genetic factors significantly influence the introduction of the disease in this geographic region.

Physical activity, cardiorespiratory fitness and risk of cutaneous malignant melanoma: Systematic review and meta-analysis

BACKGROUND

Numerous epidemiologic studies have examined the relation of physical activity or cardiorespiratory fitness to risk of cutaneous melanoma but the available evidence has not yet been quantified in a systematic review and meta-analysis.

METHODS

Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA), we identified 3 cohort studies (N = 12,605 cases) and 5 case-control studies (N = 1,295 cases) of physical activity and melanoma incidence, and one cohort study (N = 49 cases) of cardiorespiratory fitness and melanoma risk.

RESULTS

Cohort studies revealed a statistically significant positive association between high versus low physical activity and melanoma risk (RR = 1.27, 95% CI = 1.16-1.40). In contrast, case-control studies yielded a statistically non-significant inverse risk estimate for physical activity and melanoma (RR = 0.85, 95% CI = 0.63-1.14; P-difference = 0.02). The only available cohort study of cardiorespiratory fitness and melanoma risk reported a positive but statistically not significant association between the two (RR = 2.19, 95% CI = 0.99-4.96). Potential confounding by ultraviolet (UV) radiation-related risk factors was a major concern in cohort but not case-control studies.

CONCLUSIONS

It appears plausible that the positive relation of physical activity and cardiorespiratory fitness to melanoma observed in cohort studies is due to residual confounding by UV radiation-related risk factors.

IMPACT

Future prospective studies need to examine the association between physical activity, cardiorespiratory fitness and melanoma after detailed adjustment for UV radiation-related skin damage.