Association of Incident Amelanotic Melanoma With Phenotypic Characteristics, MC1R Status, and Prior Amelanotic Melanoma

Clinicopathological, dermoscopic features and circumstances of diagnosis of amelanotic or hypomelanotic melanoma: A prospective multicentric study in the French private medical sector

BACKGROUND

Amelanotic or hypomelanotic melanomas (AHM) are difficult to diagnose, and are often diagnosed late, with a high Breslow index and a poor prognosis.

PATIENTS AND METHODS

A total of 226 volunteer dermatologists consulting in private practice in France completed an online form for each new histologically proven case of melanoma diagnosed at their clinic in 2020. This anonymised survey collected data on the clinical, dermoscopic, and histological features of melanoma, as well as the circumstances of diagnosis and initial management. A group of 145 AHM was single out and compared to the 1503 pigmented melanomas (PM) from the same cohort.

RESULTS

1503 pigmented melanomas (PM) and 145 AHM (8.8% of these melanomas) were identified and included. In the AHM group, the mean age at diagnosis was 65 ± 16 years, with no significant difference from the PM control group. AHM were not predominantly on the face and neck area, and there were no differences based on gender. Warning signs (local progression and bleeding) were significantly more frequent in the AHM group than in the PM group. AHM were more frequently ulcerated and nodular, with a higher median Breslow thickness than in the PM group (1.56 vs. 0.5 mm), and mitoses were more frequent. Dermoscopy was widely used and proved useful for distinguishing benign lesions, and for highlighting the vascular polymorphous pattern of malignant lesions. Patients noticed the suspicious lesion themselves in most cases of AHM (73.2%), as opposed to their general practitioner (17.2%) or entourage (9.5%). A total body skin examination enabled detection of 19.3% of AHM and 21.3% of PM where the patient consulted for another lesion, or for an unrelated reason.

CONCLUSION

AHM are difficult to diagnose for the clinician because of the paucity or absence of pigmentary criteria. Knowledge of dermoscopic vascular patterns is critical and could help reduce the median Breslow index of AHM at the time of detection. Self-examination of the skin should be encouraged, and simple algorithms for earlier detection of skin cancers should be promoted among health professionals and the general population.

The MC1R r allele does not increase melanoma risk in MITF E318K carriers

BACKGROUND

Population-wide screening for melanoma is not cost-effective, but genetic characterization could facilitate risk stratification and targeted screening. Common Melanocortin-1 receptor (MC1R) red hair colour (RHC) variants and Microphthalmia-associated transcription factor (MITF) E318K separately confer moderate melanoma susceptibility, but their interactive effects are relatively unexplored.

OBJECTIVES

To evaluate whether MC1R genotypes differentially affect melanoma risk in MITF E318K+ vs. E318K- individuals.

MATERIALS AND METHODS

Melanoma status (affected or unaffected) and genotype data (MC1R and MITF E318K) were collated from research cohorts (five Australian and two European). In addition, RHC genotypes from E318K+ individuals with and without melanoma were extracted from databases (The Cancer Genome Atlas and Medical Genome Research Bank, respectively). χ2 and logistic regression were used to evaluate RHC allele and genotype frequencies within E318K+/- cohorts depending on melanoma status. Replication analysis was conducted on 200 000 general-population exomes (UK Biobank).

RESULTS

The cohort comprised 1165 MITF E318K- and 322 E318K+ individuals. In E318K- cases MC1R R and r alleles increased melanoma risk relative to wild type (wt), P < 0.001 for both. Similarly, each MC1R RHC genotype (R/R, R/r, R/wt, r/r and r/wt) increased melanoma risk relative to wt/wt (P < 0.001 for all). In E318K+ cases, R alleles increased melanoma risk relative to the wt allele [odds ratio (OR) 2.04 (95% confidence interval 1.67-2.49); P = 0.01], while the r allele risk was comparable with the wt allele [OR 0.78 (0.54-1.14) vs. 1.00, respectively]. E318K+ cases with the r/r genotype had a lower but not significant melanoma risk relative to wt/wt [OR 0.52 (0.20-1.38)]. Within the E318K+ cohort, R genotypes (R/R, R/r and R/wt) conferred a significantly higher risk compared with non-R genotypes (r/r, r/wt and wt/wt) (P < 0.001). UK Biobank data supported our findings that r did not increase melanoma risk in E318K+ individuals.

CONCLUSIONS

RHC alleles/genotypes modify melanoma risk differently in MITF E318K- and E318K+ individuals. Specifically, although all RHC alleles increase risk relative to wt in E318K- individuals, only MC1R R increases melanoma risk in E318K+ individuals. Importantly, in the E318K+ cohort the MC1R r allele risk is comparable with wt. These findings could inform counselling and management for MITF E318K+ individuals.

Different clinico-pathological and prognostic features of vulvar, vaginal, and cervical melanomas

Female genital tract melanoma (FGTM) is a rare and aggressive melanocytic malignancy, and its clinico-pathological and prognostic features at different anatomic sites have not yet been fully described. We retrospectively analyzed and compared the clinico-pathological data and survival outcomes of patients with primary lower genital tract melanoma enrolled between January 2005 and December 2020. We identified 95 patients with FGTM, of whom 46 had vulvar melanomas (VuM), 43 had vaginal melanomas (VaM), and six had cervical melanomas (CM). The clinical characteristics of all 95 cases, including symptoms, single or multiple primary lesions, clinical stage, surgery, and histopathological characteristics of 62 primary untreated cases, including pigmentation, predominant cytology, histological pattern, mitotic figures, and tumor-infiltrating lymphocytes of VuM, VaM, and CM, differed significantly. In comparison, only trend differences in molecular alternations were evident (p = 0.077). Disease-specific survival (DSS) was 30.7% at 5 years (46.5%, 25.6%, and 44.4% for VuM, VaM and CM, respectively). Seventy-one (85.5%) patients experienced FGTM recurrence. The median time to the first recurrence was 11 months, and VaM recurred earlier than VM and CM (16, 6, and 10 months for VuM, VaM, and CM, respectively, p = 0.038). A univariate analysis of 50 cases revealed the negative factors of disease-specific survival (DSS), including the location of the vagina and the presence of ulceration, and the negative factors of recurrence-free survival (RFS), including multiple lesions, the presence of ulceration, and the presence of lymphovascular invasion. Multiple lesions showed a borderline correlation with DSS. A multivariate Cox regression analyses of 50 cases revealed that the presence of ulceration was associated with shorter DSS and RFS (yes vs. no, Hazard Ratio = 2.400 and 2.716, respectively). Vaginal location showed a significant correlation with DSS (Hazard Ratio = 2.750, p = 0.024). In conclusion, vulval, vaginal, and cervical melanomas may differ in terms of their clinico-pathological features and associations with DSS and RFS. Ulceration and vaginal location were significantly associated with shorter DSS, and ulceration was associated with an increased risk of FGTM recurrence.

Risk Factors and Predictors of Survival Among Patients with Amelanotic Melanoma Compared to Melanotic Melanoma in the National Cancer Database

BACKGROUND

Amelanotic melanoma (AM) is a rare form of melanoma lacking pigment. Data on AM risk factors and factors predicting survival are limited.

OBJECTIVES

We sought to identify predictors of AM, survival differences in AM and melanotic melanoma, and AM-specific survival rates.

METHODS

Using 2004 through 2015 National Cancer Database data, we compared 358,543 melanoma cases to 1,384 AM cases. Multivariable logistic regression identified AM risk factors, and AM survival was explored using Kaplan-Meier and multivariable Cox regression.

RESULTS

Increased age; tumor location on the face, scalp, and neck; increased Breslow thickness; metastatic disease; ulceration; and higher mitotic rate were associated with AM. Five- and ten-year survival rates were higher for patients with MM (melanotic melanoma) than AM tumors (75.4% vs. 58.8% and 62.4% vs 45.1%; log-rank P<0.0001). No survival difference was seen after adjusting for staging factors. Among patients with AM, more recent diagnosis was associated with improved survival. Increased age, T4 tumor size, higher N-stage, metastasis, and ulceration predicted poorer survival. No survival advantage was seen for chemotherapy, immunotherapy, or radiation therapy, likely due to confounding.

CONCLUSION

AM is more common in older patients on sun-exposed skin and is diagnosed at later stages. Advanced staging at diagnosis explains the survival differences. In patients with AM, regional and metastatic disease were the primary contributors of poorer outcomes. In at-risk patients, the threshold to biopsy should be lower for suspicious nonpigmented lesions.

Influence of germline genetic variants on dermoscopic features of melanoma

Nevus count is highly determined by inherited variants and has been associated with the origin of melanoma. De novo melanomas (DNMMs) are more prevalent in patients with a low nevus count and have distinctive dermoscopic features than nevus-associated melanomas. We evaluated the impact of nine single nucleotide polymorphisms (SNPs) of MTAP (rs10811629, rs2218220, rs7023329 and rs751173), PLA2G6 (rs132985 and rs2284063), IRF4 (rs12203592), and PAX3 (rs10180903 and rs7600206) genes associated with nevus count and melanoma susceptibility, and the MC1R variants on dermoscopic features of 371 melanomas from 310 patients. All MTAP variants associated with a low nevus count were associated with regression structures (peppering and mixed regression), blue-whitish veil, shiny white structures, and pigment network. SNPs of PLA2G6 (rs132985), PAX3 (rs7600206), and IRF4 (rs12203592) genes were also associated with either shiny white structures or mixed regression (all corrected p-values ≤ .06). Melanomas from red hair color MC1R variants carriers showed lower total dermoscopy score (p-value = .015) and less blotches than melanomas from non-carriers (p-value = .048). Our results provide evidence that germline variants protective for melanoma risk and/or associated with a low nevus count are associated with certain dermoscopic features, more characteristic of de novo and worse prognosis melanomas.

Germline and somatic albinism variants in amelanotic/hypomelanotic melanoma: Increased carriage of TYR and OCA2 variants

Amelanotic/hypomelanotic melanoma is a clinicopathologic subtype with absent or minimal melanin. This study assessed previously reported coding variants in albinism genes (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, LRMDA) and common intronic, regulatory variants of OCA2 in individuals with amelanotic/hypomelanotic melanoma, pigmented melanoma cases and controls. Exome sequencing was available for 28 individuals with amelanotic/hypomelanotic melanoma and 303 individuals with pigmented melanoma, which were compared to whole exome data from 1144 Australian controls. Microarray genotyping was available for a further 17 amelanotic/hypomelanotic melanoma, 86 pigmented melanoma, 147 melanoma cases (pigmentation unknown) and 652 unaffected controls. Rare deleterious variants in TYR/OCA1 were more common in amelanotic/hypomelanotic melanoma cases than pigmented melanoma cases (set mixed model association tests P = 0.0088). The OCA2 hypomorphic allele p.V443I was more common in melanoma cases (1.8%) than controls (1.0%, X2 P = 0.02), and more so in amelanotic/hypomelanotic melanoma (4.4%, X2 P = 0.007). No amelanotic/hypomelanotic melanoma cases carried an eye and skin darkening haplotype of OCA2 (including rs7174027), present in 7.1% of pigmented melanoma cases (P = 0.0005) and 9.4% controls. Variants in TYR and OCA2 may play a role in amelanotic/hypomelanotic melanoma susceptibility. We suggest that somatic loss of function at these loci could contribute to the loss of tumor pigmentation, consistent with this we found a higher rate of somatic mutation in TYR/OCA2 in amelanotic/hypomelanotic melanoma vs pigmented melanoma samples (28.6% vs 3.0%; P = 0.021) from The Cancer Genome Atlas Skin Cutaneous Melanoma collection.

Uncommon Subtypes of Malignant Melanomas: A Review Based on Clinical and Molecular Perspectives

Malignant melanoma represents the most aggressive type of skin cancer. Modern therapies, including targeted agents and immune checkpoint inhibitors, have changed the dismal prognosis that characterized this disease. However, most evidence was obtained by studying patients with frequent subtypes of cutaneous melanoma (CM). Consequently, there is an emerging need to understand the molecular basis and treatment approaches for unusual melanoma subtypes. Even a standardized definition of infrequent or rare melanoma is not clearly established. For that reason, we reviewed this challenging topic considering clinical and molecular perspectives, including uncommon CMs-not associated with classical V600E/K BRAF mutations-malignant mucosal and uveal melanomas, and some unusual independent entities, such as amelanotic, desmoplastic, or spitzoid melanomas. Finally, we collected information regarding melanomas from non-traditional primary sites, which emerge from locations as unique as meninges, dermis, lymph nodes, the esophagus, and breasts. The aim of this review is to summarize and highlight the main scientific evidence regarding rare melanomas, with a particular focus on treatment perspectives.

Clinicopathological and dermoscopic features of amelanotic and hypomelanotic melanoma: a retrospective multicentric study

BACKGROUND

Amelanotic and hypomelanotic melanoma (AHM) has a higher risk of delayed diagnosis and a significant lower 5-year melanoma-specific survival compared to pigmented melanoma. Our aim was the evaluation of the clinicopathological/dermoscopic features of amelanotic melanoma (AM) and hypomelanotic melanoma (HM).

METHODS

All participants had a personal history of AHM. We defined HM as showing clinical/dermoscopic pigmentation in < 25% of the lesion's surface and histopathological focal pigmentation, while AM as melanomas with clinical/dermoscopic and histopathological absence of pigmentation.

RESULTS

The most common phenotypic traits among the 145 AHM patients were as follows: phototype II, blue-grey eyes, and dark brown hair. Red hair was present in 23.8% AHM cases (AM = 22.60%; HM = 25.80%). The most affected area was the back (29.5%). A total of 67.1% were classified as AM and 32.9% as HM. The most represented hair colors in AM and HM were, respectively, blonde and dark brown hair. Median Breslow thickness was 1.7 mm, superficial spreading melanoma (SSM) and nodular melanoma (NM) were the most represented histotypes, and mitotic rate > 1 × mm² was reported in 73.3% cases, and regression was significantly more present in HM. Dermoscopy showed high prevalence of white structureless zones (63.4%), linear looped vessels (58.8%), linear irregular vessels (50.0%), and arborizing vessels (47.2%). Multivariate logistic regression confirmed the association between the presence of pigmentation and the following: histological regression, dermoscopic globules, and arborizing vessels.

CONCLUSIONS

Predominance of red hair in AHM patients was not confirmed. AHM affects mostly intermittent sun-exposed body areas. The deeper median Breslow thickness (versus pigmented melanoma), the association of AM with the nodular histotype, and the high mitotic rate highlight the AHM's aggressiveness. HM's higher levels of regression can be explained by the presence of pigmentation, driving the underlying immune response. AHM showed a polymorphous vascular pattern and significant presence of arborizing vessels (especially HM).

Phenotypic and genotypic analysis of amelanotic and hypomelanotic melanoma patients

BACKGROUND

Amelanotic/hypomelanotic melanoma is associated with poorer outcomes due to a more advanced disease stage at diagnosis.

OBJECTIVE

To determine phenotypic risks and genotypic associations with amelanotic/hypomelanotic melanoma to develop a clinical and genetic profile that could assist in identifying high-risk individuals.

METHODS

The Brisbane Naevus Morphology Study conducted from 2009 to 2016 has recruited a core of 1254 participants. Participants were drawn from a combination of volunteers from dermatology outpatient clinics, private dermatology clinics, the Brisbane Longitudinal Twin Study and QSkin study. Case participants had a personal history of melanoma and control participants no personal history of melanoma. We specifically examined seven known candidate pigmentation and melanoma genes and pigmentary phenotypic characteristics in participants with amelanotic/hypomelanotic melanoma compared to pigmented melanomas. This assayed single nucleotide polymorphisms in MC1R, TYR, HERC/OCA2, IRF4, MTAP, PLA2G6 and MITF.

RESULTS

Forty-seven participants had at least one amelanotic/hypomelanotic melanoma, and 389 had pigmented melanomas, with amelanotic/hypomelanotic melanoma patients significantly older than pigmented melanoma participants (63.3 ± 13.0 vs. 54.6 ± 15.3 years; P < 0.001). Amelanotic/hypomelanotic melanoma patients were more likely than pigmented melanoma patients to have red hair (34% vs. 15%; P = 0.01), severe hand freckling (13% vs. 5%; P = 0.01) and propensity to sunburn (63% vs. 44%; P = 0.01). MC1R R/R genotype was much more frequent in our amelanotic/hypomelanotic melanoma population (31.1% vs. 11%; P < 0.001; OR 26.4 vs. 5.9; control 1.0). Amelanotic/hypomelanotic melanoma was associated with TYR rs1126809*A/A [OR (CI 95%) 2.7 (1.1-6.8) vs. 1.2 (0.8-1.9)] and PLA2G6 rs11570734*A/A [OR (CI 95%) 3.7 (1.0-13.6) vs. 1.3 (0.9-2.0)]. The MTAP melanoma risk SNP genotype, associated with darker pigmentation, (rs4636294*A/A) was less common in amelanotic/hypomelanotic melanoma patients [OR (CI 95%) 0.8 (0.3-2.1) vs. 2.0 (1.3-3.1)].

CONCLUSIONS

Knowledge of phenotypic and genotypic associations of amelanotic/hypomelanotic melanoma can help predict risks and associations of this difficult to diagnose melanoma, which may ultimately assist clinical management and patient skin self-examination.

Incidence, Mortality, and Spatiotemporal Distribution of Cutaneous Malignant Melanoma Cases Across Canada

Background:

We recently reported a steady increase in the incidence and mortality of cutaneous malignant melanoma (CMM) in Canada during 1992-2010.

Objectives:

The objective of this article is to examine the distribution of Canadian CMM patients at the level of provinces, cities, and forward sortation area (FSA) postal codes.

Methods:

Using 3 Canadian population-based registries, we conducted an in-depth examination of the incidence and mortality trends for 72 565 Canadian CMM patients over the period 1992-2010.

Results:

We found that among 20- to 39-year-olds, the incidence of CMM in women (7.17 per 100 000 individuals) was significantly higher than in men (4.60 per 100 000 individuals per year). Women age 80 years and older had an incidence of CMM (58.46 cases per 100 000 women per year) more than 4 times greater than the national average (12.29 cases per 100 000 population per year) and a corresponding high mortality rate (20.18 deaths per 100 000 women per year), when compared with the Canadian melanoma mortality of 2.4 deaths per 100 000 per year. In other age groups men had higher incidence and corresponding melanoma mortality rates. We also studied CMM incidence by province, city, and FSA postal codes and identified several high-incidence communities that were located near the coast/waterfronts. In addition, plotting latitude measures for cities and FSAs vs CMM incidence rate confirmed the inverse relationship between geographical latitude and incidence of melanoma in Canada (slope = –0.22 ± 0.05).

Conclusions:

This research may help develop sex-, age- and geographic region-specific recommendations to decrease the future burden of CMM in Canada.

Clinicopathologic, misdiagnosis, and survival differences between clinically amelanotic melanomas and pigmented melanomas

BACKGROUND

Amelanotic malignant melanoma (AMM) is challenging to diagnose. Clinical risk factors for AMM are not well defined.

OBJECTIVE

To investigate clinicopathologic, misdiagnosis, and survival differences between patients with AMM and those with pigmented malignant melanoma (PMM).

METHODS

A cross-sectional retrospective medical record review at a tertiary academic medical center.

RESULTS

A total of 933 patients with melanoma with known presenting tumor color were identified (342 with AMM vs 591 with PMM). AMM was associated with older age, history of nonmelanoma skin cancer, and red hair, whereas AMM was inversely associated with a family history of melanoma, more than 50 nevi, and a history of dysplastic nevi. Compared with PMM, AMM was more likely to be located on the head and/or neck, had more aggressive pathologic features (greater Breslow depth and/or mitoses, ulceration, nodular subtype), and was less likely to be associated with a precursor nevus or regression. Finally, patients with AMM were more likely to be misdiagnosed than were patients with PMM (25% vs 12% clinically and 12% vs 7% pathologically), and they had poorer melanoma-specific survival (5-year overall survival rate, 0.77 [95% confidence interval, 0.72-0.82] vs 0.84 [95% confidence interval, 0.80-0.87]).

LIMITATIONS

Retrospective study design, single-institutional study.

CONCLUSION

Greater clinician awareness, lower biopsy thresholds, and increased patient education may be useful to enhance AMM detection in patients with certain characteristics.

Inherited Genetic Variants Associated with Melanoma BRAF/NRAS Subtypes

BRAF and NRAS mutations arise early in melanoma development, but their associations with low-penetrance melanoma susceptibility loci remain unknown. In the Genes, Environment and Melanoma Study, 1,223 European-origin participants had their incident invasive primary melanomas screened for BRAF/NRAS mutations and germline DNA genotyped for 47 single-nucleotide polymorphisms identified as low-penetrant melanoma-risk variants. We used multinomial logistic regression to simultaneously examine each single-nucleotide polymorphism's relationship to BRAF V600E, BRAF V600K, BRAF other, and NRAS+ relative to BRAF-/NRAS- melanoma adjusted for study features. IRF4 rs12203592*T was associated with BRAF V600E (odds ratio [OR] = 0.59, 95% confidence interval [CI] = 0.43-0.79) and V600K (OR = 0.65, 95% CI = 0.41-1.03), but not BRAF other or NRAS+ melanoma. A global test of etiologic heterogeneity (Pglobal = 0.001) passed false discovery (Pglobal = 0.0026). PLA2G6 rs132985*T was associated with BRAF V600E (OR = 1.32, 95% CI = 1.05-1.67) and BRAF other (OR = 1.82, 95% CI = 1.11-2.98), but not BRAF V600K or NRAS+ melanoma. The test for etiologic heterogeneity (Pglobal) was 0.005. The IRF4 rs12203592 associations were slightly attenuated after adjustment for melanoma-risk phenotypes. The PLA2G6 rs132985 associations were independent of phenotypes. IRF4 and PLA2G6 inherited genotypes may influence melanoma BRAF/NRAS subtype development.

Clinically amelanotic or hypomelanotic melanoma: Anatomic distribution, risk factors, and survival

BACKGROUND

The recognition and diagnosis of clinically amelanotic or hypomelanotic melanoma is a challenge.

OBJECTIVE

This study aimed to examine the anatomic distribution and risk factors associated with clinically amelanotic or hypomelanotic melanoma and compare the survival of patients with clinically amelanotic or hypomelanotic melanoma with that of patients with pigmented melanoma.

METHODS

A prospective cohort study of all cases of primary invasive melanoma managed at a tertiary referral center was performed.

RESULTS

There were a total of 3913 invasive melanomas, and 384 (9.8%) were clinically amelanotic or hypomelanotic. Skin phototype I; red as well as blonde hair color; actinic keratoses; nodular, desmoplastic, and lentigo maligna subtype; increased Breslow thickness; and mitoses were independently associated with amelanotic or hypomelanotic melanoma (P < .05). After adjustment for subtype and thickness, the face, ears, lateral aspect of the neck, upper portion of the arm, posterior aspect of the forearm, dorsal aspect of the hand, and anterior aspect of the lower portion of the leg were associated with increased odds of amelanotic or hypomelanotic melanoma when compared with the upper portion of the back (P < .05). Mortality risk from melanoma appeared greater for amelanotic or hypomelanotic melanoma than for pigmented melanoma (hazard ratio, 1.5; 95% confidence interval, 1.1-2.1) but was similar once Breslow thickness was taken into account.

LIMITATIONS

Single tertiary referral center.

CONCLUSION

Although clinically amelanotic or hypomelanotic melanoma can occur on all body sites, it is more common on chronically sun-exposed areas. Clinicians should have an increased index of suspicion in patients with a sun-sensitive skin phenotype, red hair, and associated actinic keratoses.

Concordance of somatic mutational profile in multiple primary melanomas

This study aimed to determine the frequency and concordance of BRAF and NRAS mutation in tumours arising in patients with multiple primary melanoma (MPM). Patients with MPM managed at one of three tertiary referral centres in Melbourne, Australia, from 2010 to 2015 were included. Incident and subsequent melanomas underwent mutation testing. Cohen's kappa (κ) coefficient assessed agreement between incident and subsequent primary melanomas for both BRAF and NRAS mutation status (mutant versus wild-type). Mutation testing of at least two primary tumours from 64 patients was conducted. There was poor agreement for both BRAF and NRAS mutation status between incident and subsequent melanomas (κ = 0.10, 95% CI -0.10 to 0.42; κ = 0.06, 95% CI -0.10 to 0.57, respectively). In view of the low concordance in BRAF mutation status between incident and subsequent melanomas, mutational analysis of metastatic tissue, rather than of a primary melanoma, in patients with MPM should be used to guide targeted therapy.

Nanomechanical Phenotype of Melanoma Cells Depends Solely on the Amount of Endogenous Pigment in the Cells

Cancer cells have unique nanomechanical properties, i.e., they behave as if they were elastic. This property of cancer cells is believed to be one of the main reasons for their facilitated ability to spread and metastasize. Thus, the so-called nanomechanical phenotype of cancer cells is viewed as an important indicator of the cells’ metastatic behavior. One of the most highly metastatic cancer cells are melanoma cells, which have a very unusual property: they can synthesize the pigment melanin in large amounts, becoming heavily pigmented. So far, the role of melanin in melanoma remains unclear, particularly the impact of the pigment on metastatic behavior of melanoma cells. Importantly, until recently the potential mechanical role of melanin in melanoma metastasis was completely ignored. In this work, we examined melanoma cells isolated from hamster tumors containing endogenous melanin pigment. Applying an array of advanced microscopy and spectroscopy techniques, we determined that melanin is the dominating factor responsible for the mechanical properties of melanoma cells. Our results indicate that the nanomechanical phenotype of melanoma cells may be a reliable marker of the cells’ metastatic behavior and point to the important mechanical role of melanin in the process of metastasis of melanoma.