Comparison of clinicopathologic features and survival of histopathologically amelanotic and pigmented melanomas: a population-based study

Primary Alopecia Neoplastica: A Novel Case Report and Literature Review

Alopecia neoplastica (AN) is caused by neoplastic cells damaging hair follicles, resulting in patchy hair loss like cicatricial alopecia and alopecia areata. AN has predominantly described cutaneous metastasis to the scalp from primary visceral malignant tumors. Less frequently, AN results from a primary scalp neoplasm. Compared to "secondary AN," there is a paucity of literature on "primary AN." Herein, we present a comprehensive literature review of primary AN and introduce a unique case of amelanotic melanoma causing primary AN. Including our presented case, 11 cases of primary AN have been reported with causative scalp neoplasms including angiosarcoma, hemangioendothelioma, syringomatous carcinoma, ectopic extramammary Paget's disease, and primary desmoplastic melanoma. 27.3% (3 of 11) of cases were misdiagnosed and treated for a primary alopecia, and 36.4% (4 of 11) of lesions were present for multiple years or an unknown amount of time, likely due to difficulty in recognizing scalp lesion or misdiagnosis. All patients required surgical excision with 36.4% (4 of 11) requiring chemotherapy, radiation, or photodynamic therapy. Two patients with scalp angiosarcoma died from their aggressive disease. Due to the risks of malignant primary AN if allowed to progress, primary AN should be considered in patients presenting with scarring alopecia.

Melanization as unfavorable factor in amelanotic melanoma cell biology

The biology of three amelanotic melanoma cell lines (Ab, B16F10, and A375) of different species origin was analyzed during in vitro induced melanization in these cells. Melanin production was induced by DMEM medium characterized by a high level of L-tyrosine (a basic amino acid for melanogenesis). The biodiversity of amelanotic melanoma cells was confirmed by their different responses to melanogenesis induction; Ab hamster melanomas underwent intensive melanization, mouse B16F10 darkened slightly, while human A375 cells did not show any change in melanin content. Highly melanized Ab cells entered a cell death pathway, while slight melanization did not influence cell biology in a significant way. The rapid and high melanization of Ab cells induced apoptosis documented by phosphatidylserine externalization, caspase activation, and mitochondrial energetic state decrease. Melanoma cell type, culture medium, and time of incubation should be taken into consideration during amelanotic melanoma cell culture in vitro. L-tyrosine, as a concentration-dependent factor presented in the culture media, could stimulate some amelanotic melanoma cell lines (Ab, B16F10) to melanin production. The presence of melanin should be considered in the examination of antimelanoma compounds in vitro, because induction of melanin may interfere or be helpful in the treatment of amelanotic melanoma.

Management of Noncutaneous Melanomas

Noncutaneous melanomas are rare subtypes of melanoma with high rates of metastatic disease and poor overall survival. One-third to one-half of cases are amelanotic, which may contribute to a delay in diagnosis. Immunohistochemistry staining with typical melanoma markers helps confirm the diagnosis. There is no standard staging system across mucosal melanomas. Elective nodal dissection is not recommended and there is a paucity of data to support use of sentinel lymph node biopsy. Mutational analysis should be routinely performed. Systemic therapy options include targeted inhibitors, immunotherapy, and cytotoxic chemotherapy, although further studies are needed to confirm their efficacy.

Adenoviral CD40 Ligand Immunotherapy in 32 Canine Malignant Melanomas-Long-Term Follow Up

Malignant melanoma is a serious disease in both humans and dogs, and the high metastatic potential results in poor prognosis for many patients. Its similarities with human melanoma make spontaneous canine melanoma an excellent model for comparative studies of novel therapies and tumor biology. Gene therapy using adenoviruses encoding the immunostimulatory gene CD40L (AdCD40L) has shown promise in initial clinical trials enrolling human patients with various malignancies including melanoma. We report a study of local AdCD40L treatment in 32 cases of canine melanoma (23 oral, 5 cutaneous, 3 ungual and 1 conjunctival). Eight patients were World Health Organization (WHO) stage I, 9 were stage II, 12 stage III, and 3 stage IV. One to six intratumoral injections of AdCD40L were given every seven days, combined with cytoreductive surgery in 20 cases and only immunotherapy in 12 cases. Tumor tissue was infiltrated with T and B lymphocytes after treatment, suggesting immune stimulation. The best overall response based on result of immunotherapy included 7 complete responses, 5 partial responses, 5 stable and 2 progressive disease statuses according to the World Health Organization response criteria. Median survival was 285 days (range 20–3435 d). Our results suggest that local AdCD40L therapy is safe and could have beneficial effects in dogs, supporting further treatment development. Clinical translation to human patients is ongoing.

Microbeam Radiotherapy-A Novel Therapeutic Approach to Overcome Radioresistance and Enhance Anti-Tumour Response in Melanoma

Melanoma is the deadliest type of skin cancer, due to its invasiveness and limited treatment efficacy. The main therapy for primary melanoma and solitary organ metastases is wide excision. Adjuvant therapy, such as chemotherapy and targeted therapies are mainly used for disseminated disease. Radiotherapy (RT) is a powerful treatment option used in more than 50% of cancer patients, however, conventional RT alone is unable to eradicate melanoma. Its general radioresistance is attributed to overexpression of repair genes in combination with cascades of biochemical repair mechanisms. A novel sophisticated technique based on synchrotron-generated, spatially fractionated RT, called Microbeam Radiation Therapy (MRT), has been shown to overcome these treatment limitations by allowing increased dose delivery. With MRT, a collimator subdivides the homogeneous radiation field into an array of co-planar, high-dose microbeams that are tens of micrometres wide and spaced a few hundred micrometres apart. Different preclinical models demonstrated that MRT has the potential to completely ablate tumours, or significantly improve tumour control while dramatically reducing normal tissue toxicity. Here, we discuss the role of conventional RT-induced immunity and the potential for MRT to enhance local and systemic anti-tumour immune responses. Comparative gene expression analysis from preclinical tumour models indicated a specific gene signature for an 'MRT-induced immune effect'. This focused review highlights the potential of MRT to overcome the inherent radioresistance of melanoma which could be further enhanced for future clinical use with combined treatment strategies, in particular, immunotherapy.

Not all melanomas are created equal: a review and call for more research into nodular melanoma

Among the histogenic subtypes of melanoma, nodular melanoma (NM) is the major contributor for thicker and fatal melanomas and it has been associated with melanoma-specific death in thin tumours, highlighting an important subgroup of 'aggressive thin' melanomas. This review provides a synthesis of the distinct characteristics of NM, with respect to epidemiology and risk factors, clinical presentation, histopathology, molecular and dermoscopic aspects, and screening practices. The real challenges are to find better biomarkers of aggressiveness and to know whether the control of such aggressive melanomas can be influenced by targeted interventions such as early detection, drug interventions and preventive strategies.

Female Genital Tract Melanoma: 10 Years of Experience at a Single Tertiary Center

OBJECTIVE

Malignant melanoma of the female genital tract is a rare disease with poor prognosis, with controversies remaining in its staging and management. In this study, we investigate clinical, pathological, and outcome data for patients referred to a tertiary cancer center with female genital tract melanoma over a decade.

METHODS

Patients were retrospectively identified using a search of pathology reports to identify all cases of female genital tract melanoma from 2007 to 2019. Electronic patient records were used to record clinical information. Histopathology specimens were reviewed by a gynecological and dermatological pathology specialist.

RESULTS

We identified 30 cases of genital tract melanoma, of which 19 were vulvar, 10 were vaginal, and 1 cervical. Overall survival at 1, 3, and 5 years was found to be 80%, 60%, and 57%. Patients who died were not significantly older at presentation than patients who survived (62 y vs 69 y, p = .215). No association was found between mortality and microscopic ulceration, lymphovascular invasion, pigmentation, resection margins, or radical versus local surgery.Nonvulvar lesions were significantly associated with mortality compared with vulvar lesions (p = .0018), despite similar age and Breslow thickness. Five patients were diagnosed at in situ stage, all of these were vulvar. Even after excluding these melanomas in situ, nonvulvar melanomas still had a significantly worse mortality rate (p = .048). A higher proportion of nonvulvar lesions than vulvar lesions displayed loss of pigmentation (p = .026).

CONCLUSIONS

Nonvulvar genital tract melanomas carry a significantly worse prognosis. Survival was not related to resection margins, supporting the use of more conservative surgical margins.

The dark side of daylight: photoaging and the tumor microenvironment in melanoma progression

Continued thinning of the atmospheric ozone, which protects the earth from damaging ultraviolet radiation (UVR), will result in elevated levels of UVR reaching the earth's surface, leading to a drastic increase in the incidence of skin cancer. In addition to promoting carcinogenesis in skin cells, UVR is a potent extrinsic driver of age-related changes in the skin known as "photoaging." We are in the preliminary stages of understanding of the role of intrinsic aging in melanoma, and the tumor-permissive effects of photoaging on the skin microenvironment remain largely unexplored. In this Review, we provide an overview of the impact of UVR on the skin microenvironment, addressing changes that converge or diverge with those observed in intrinsic aging. Intrinsic and extrinsic aging promote phenotypic changes to skin cell populations that alter fundamental processes such as melanogenesis, extracellular matrix deposition, inflammation, and immune response. Given the relevance of these processes in cancer, we discuss how photoaging might render the skin microenvironment permissive to melanoma progression.

Benzamide derivative radiotracers targeting melanin for melanoma imaging and therapy: Preclinical/clinical development and combination with other treatments

Cutaneous melanoma arises from proliferating melanocytes, cells specialized in the production of melanin. This property means melanin can be considered as a target for monitoring melanoma patients using nuclear imaging or targeted radionuclide therapy (TRT). Since the 1970s, many researchers have shown that specific molecules can interfere with melanin. This paper reviews some such molecules: benzamide structures improved to increase their pharmacokinetics for imaging or TRT. We first describe the characteristics and biosynthesis of melanin, and the main features of melanin tracers. The second part summarizes the preclinical and corresponding clinical studies on imaging. The last section presents TRT results from ongoing protocols and discusses combinations with other therapies as an opportunity for melanoma non-responders or patients resistant to treatments.

Anticancer Properties of Amino Acid and Peptide Derivatives of Mycophenolic Acid

BACKGROUND

Although Mycophenolic Acid (MPA) is applied as prodrugs in clinic as an immunosuppressant, it also possesses anticancer activity. MPA acts as Inosine-5'-Monophosphate Dehydrogenase (IMPDH) inhibitor, where the carboxylic group at the end of the side chain interacts with Ser 276 of the enzyme via hydrogen bonds. Therefore, MPA derivatives with other polar groups indicated high inhibition too. On the other hand, potent anticancer agents like dacarbazine and cisplatin give numerous side-effects.

OBJECTIVE

Based on the literature data, MPA derivatives should be explored towards anticancer properties. Conversion of the carboxylic group of MPA to amide could maintain antiproliferative activity. Therefore, we decided to investigate several amino acid and peptide derivatives of MPA against chosen cancer cell lines in vitro.

METHODS

Amides of MPA hold threonine and arginine amino acid unit. These amino acid derivatives were tested as L and D enantiomers and both in free acid and methyl esters forms. Additionally, MPA was modified with tuftsin or retro-tuftsin as biologically active peptides, which could act as a drug carrier.

RESULTS

Amino acid and peptide derivatives of MPA were investigated in vitro as potential anticancer agents on cell lines: Ab melanoma, A375 melanoma and SHSY5Y neuroblastoma. The activity of the tested compounds was compared to parent MPA and known chemotherapeutics: dacarbazine and cisplatin.

CONCLUSION

Amino acid moiety and the sequence of amino acids in the peptide part influenced observed activity. The most active amino acid MPA analogues occurred to be D and L-threonine derivatives as methyl esters, probably due to better cell membrane penetration.

PET Imaging of Melanoma Using Melanin-Targeted Probe

Melanin exists in the most of melanoma lesions. Melanin plays an important role in melanoma progression, metastasis, therapy response, and the overall survival of patients. Therefore, melanin is a critical target for melanoma diagnosis and therapy. Many melanin targeting probes, such as radioisotope-labeled benzamide analogs, have been developed for melanoma diagnosis using positron emission tomography (PET). The N-(2-(diethylamino)-ethyl)-¹⁸F-5-fluoropicolinamide (¹⁸F-P3BZA) probe is one of the benzamide analogs and has been preliminarily tested for clinical diagnosis of melanoma in our recent studies. It has shown high specificity and favorable in vivo performance for PET of melanoma. Herein, we describe the detailed synthesis protocol of ¹⁸F-P3BZA and PET/CT imaging procedure for animal models and patients.

A Rare Case of Oral Mucosal Amelanotic Melanoma in a 77-year-old Immunocompromised Man

Primary mucosal melanomas are rare neoplasms that occur in the mouth, esophagus, nasopharynx, larynx, and anogenital mucosa. Mucosal melanomas are rare, accounting for approximately one percent of all melanomas. Of the mucosal melanomas that occur in the head and neck, oral mucosal melanomas compose approximately 25 percent. Here, we present a case of an amelanotic oral mucosal melanoma of the mucosal lip in a 77-year-old male patient with a history of non-Hodgkin's lymphoma and multiple basal and squamous cell carcinomas. The patient presented with a pink, nonpigmented, pedunculated mass on the left superior mucosal lip. Histopathologic examination of the biopsy specimen revealed a diagnosis of a superficial spreading type of malignant melanoma with a nodular component. The patient was referred to a tertiary care center for further management. Multiple risk factors exist for developing melanoma, including immunosuppression. Lymphoproliferative disorders, such as non-Hodgkin's lymphoma, lead to inherent immunosuppression, which can be exacerbated by chemotherapy treatments. Cases of oral mucosal melanoma have a poor prognosis due to delayed diagnosis, anatomic location, and aggressive behavior. Surgical resection is first-line therapy, with regional lymph-node dissection of the neck is recommended in most cases. Radiotherapy and targeted molecular therapy, such as c-KIT inhibitors, can also be used.

A Rare Case of Osteoinvasive Amelanotic Melanoma of the Nail Unit

Introduction

Amelanotic melanoma is a rare subtype, which may be clinically difficult to diagnose due to lack of pigmentation and variable histopathological features. Osteoinvasion is another rare characteristic of melanoma. There are few reports in the literature of amelanotic melanoma of the nail unit (nail bed, matrix, and nail folds) with invasion of bone.

Case Presentation

We present a case of a 73-year-old Caucasian male with a 13-month history of an ungual lesion on his right hallux. The lesion was initially treated as a chronic diabetic ulceration with failure to resolve with standard of care.

Discussion/Conclusion

A heightened index of suspicion for a malignant process is necessary when standard of care fails to lead to improvement or resolution. In these instances, biopsy should be seriously considered.

Amelanotic melanoma of the head and neck: analysis of tumor characteristics from the National Cancer Database

BACKGROUND

Amelanotic melanoma is an extremely rare subtype of cutaneous melanoma. The tumor characteristics are still not well understood, especially for those located in the head and neck.

METHODS

Tumor characteristics of patients diagnosed with amelanotic melanoma of the head and neck (AMHN) from January 1, 2004, to December 31, 2015, were analyzed by querying the National Cancer Database. Characteristics of AMHN were subsequently compared with common malignant melanoma of the head and neck (CMMHN).

RESULTS

Three hundred and sixty-eight patients were diagnosed with AMHN, and 69,267 were diagnosed with CMMHN. Of those with AMHN, 128 (34.8%) had melanoma located on the scalp and neck, and 172 (46.7%) were diagnosed with an early disease stage (i.e., 0, I, or II). When compared with CMMHN, patients with AMHN were more likely to be diagnosed after 80 years of age (25.3% vs. 18.2%; odds ratio [OR], 3.28; 95% CI, 1.09-9.84; P = 0.03), when Breslow depth was between 2.01 and 4.00 mm (28.5% vs. 6.5%; OR, 1.92; 95% CI, 1.15-3.19; P = 0.01), when ulceration was present (36.7% vs. 9.0%; OR, 1.99; 95% CI, 1.34-2.97; P = 0.001), and when mitotic count was 1 or more/mm² (40.5% vs. 12.8%; OR; 2.53; 95% CI, 1.09-5.89; P = 0.03). No statistical difference was found for sex, specific location, stage, or lymph node involvement.

CONCLUSION

Our study determined that AMHN is associated with older age, increased Breslow depth, presence of ulceration, and greater mitotic count when compared with CMMHN.

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.

Chloroacridine derivatives as potential anticancer agents which may act as tricarboxylic acid cycle enzyme inhibitors

PURPOSE

This paper concerns the cytotoxicity of 9-chloro-1-nitroacridine (1a) and 9-chloro-4-methyl-1-nitroacridine (1b) against two biologically different melanoma forms: melanotic and amelanotic. Melanomas are tumors characterized by high heterogeneity and poor susceptibility to chemotherapies. Among new analogs synthesized by us, compound 1b exhibited the highest anticancer potency. Because of that, in this study, we analyzed the mechanism of action for 1a and its 4-methylated derivative, 1b, against a pair of biological melanoma forms, with regard to proliferation, cell death mechanism and energetic state.

METHODS

Cytotoxicity was evaluated by XTT assay. Cell death was estimated by plasma membrane structure changes (phosphatidylserine externalization), caspase activation, and ROS presence. The energetic state of cells was estimated based on NAD and ATP levels, and the activity of tricarboxylic acid cycle enzymes (pyruvate dehydrogenase complex, aconitase, isocitrate dehydrogenase).

RESULTS

The chloroacridines affect biological forms of melanoma in different ways. Amelanotic (Ab) melanoma (with inhibited melanogenesis and higher malignancy) was particularly sensitive to the action of the chloroacridines. The Ab melanoma cells died through apoptosis and through death without caspase activation. Diminished activity of TAC enzymes was noticed among Ab melanoma cells together with ATP/NAD depletion, especially in the case of 1b.

CONCLUSION

Our data show that the biological forms of the tumors responded to 1a and its 4-methylated analog in different ways. 1a and 1b could be inducers of regulated melanoma cell death, especially the amelanotic form. Although the mechanism of the cell death is not fully understood, 1b may act by interfering with the TAC enzymes and blocking specific pathways leading to tumor growth. This could encourage further investigation of its anticancer activity, especially against the amelanotic form of melanoma.

Role of Melanin Chemiexcitation in Melanoma Progression and Drug Resistance

Melanoma is the deadliest type of skin cancer. Human melanomas often show hyperactivity of nitric oxide synthase (NOS) and NADPH oxidase (NOX), which, respectively, generate nitric oxide (NO ^· ) and superoxide (O₂ ^·- ). The NO ^· and O₂ ^- react instantly with each other to generate peroxynitrite (ONOO^-) which is the driver of melanin chemiexcitation. Melanoma precursors, the melanocytes, are specialized skin cells that synthesize melanin, a potent shield against sunlight's ultraviolet (UV) radiation. However, melanin chemiexcitation paradoxically demonstrates the melanomagenic properties of melanin. In a loop, the NOS activity regulates melanin synthesis, and melanin is utilized by the chemiexcitation pathway to generate carcinogenic melanin-carbonyls in an excited triplet state. These carbonyl compounds induce UV-specific DNA damage without UV. Additionally, the carbonyl compounds are highly reactive and can make melanomagenic adducts with proteins, DNA and other biomolecules. Here we review the role of the melanin chemiexcitation pathway in melanoma initiation, progression, and drug resistance. We conclude by hypothesizing a non-classical, positive loop in melanoma where melanin chemiexcitation generates carcinogenic reactive carbonyl species (RCS) and DNA damage in normal melanocytes. In parallel, NOS and NOX regulate melanin synthesis generating raw material for chemiexcitation, and the resulting RCS and reactive nitrogen species (RNS) regulate cellular proteome and transcriptome in favor of melanoma progression, metastasis, and resistance against targeted therapies.

Oral Amelanotic Melanomas: Clinicopathologic Features of 8 Cases and Review of the Literature

Mucosal melanomas are aggressive tumors, rarely observed in the oral cavity. The diagnosis is based on the clinical and microscopical features. Often these tumors had variable amounts of melanin pigmentation. However, when melanin is absent, the tumors are denominated amelanotic, presenting a tendency to misdiagnosis and delayed treatment. The aim of this study was to describe the clinicopathologic features of a series of oral amelanotic melanomas (OAM). Records of all cases of OAM were retrospectively retrieved from oral pathology services from January 2002 to January 2019. Data regarding the clinical features, morphological aspects, immunohistochemical reactions, treatment, and follow-up status were collected. Eight cases of OAM were included, 6 in men and 2 in women (ratio of 3:1) ranging in age from 33 to 77 years (mean 53.6 years). Clinically, the tumors presented as masses or ulcerated swellings. The most common intraoral locations of the tumors were gingiva and palate. Cervical lymph node metastasis was detected in 3 patients at the first examination. All but one patient died from complications of the tumors after a mean follow-up period of 8.5 months. In conclusion, OAM is a very aggressive malignant tumor, and when melanin is absent, an immunohistochemical panel comprising S100, melan A, HMB45, and SOX10 should be performed.

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).

Intravital Imaging of Adoptive T-Cell Morphology, Mobility and Trafficking Following Immune Checkpoint Inhibition in a Mouse Melanoma Model

Efficient T-cell targeting, infiltration and activation within tumors is crucial for successful adoptive T-cell therapy. Intravital microscopy is a powerful tool for the visualization of T-cell behavior within tumors, as well as spatial and temporal heterogeneity in response to immunotherapy. Here we describe an experimental approach for intravital imaging of adoptive T-cell morphology, mobility and trafficking in a skin-flap tumor model, following immune modulation with immune checkpoint inhibitors (ICIs) targeting PD-L1 and CTLA-4. A syngeneic model of ovalbumin and mCherry-expressing amelanotic mouse melanoma was used in conjunction with adoptively transferred OT-1+ cytotoxic T-cells expressing GFP to image antigen-specific live T-cell behavior within the tumor microenvironment. Dynamic image analysis of T-cell motility showed distinct CD8+ T-cell migration patterns and morpho-dynamics within different tumor compartments in response to ICIs: this approach was used to cluster T-cell behavior into four groups based on velocity and meandering index. The results showed that most T-cells within the tumor periphery demonstrated Lévy-like trajectories, consistent with tumor cell searching strategies. T-cells adjacent to tumor cells had reduced velocity and appeared to probe the local environment, consistent with cell-cell interactions. An increased number of T-cells were detected following treatment, traveling at lower mean velocities than controls, and demonstrating reduced displacement consistent with target engagement. Histogram-based analysis of immunofluorescent images from harvested tumors showed that in the ICI-treated mice there was a higher density of CD31+ vessels compared to untreated controls and a greater infiltration of T-cells towards the tumor core, consistent with increased cellular trafficking post-treatment.

Prognostic impact of HERC2 protein and pink-eyed dilution protein in uveal melanoma

Biological understanding of pigmentation and its association with clinicopathological implications in uveal melanoma (UM) risk is still unexplored. HECT and RLD Domain Containing E3 Ubiquitin Protein Ligase 2 (HERC2) and Pink-eyed dilution protein (P-protein) are the important markers that regulate pigmentation in eye. Therefore, our aim of the study was to investigate the expression of HERC2 and P-protein in the UM patients and correlate with patient outcome. Fifty-two formalin-fixed paraffin-embedded UM tissue samples were included to detect the expression of HERC2 and P-protein by immunohistochemistry and validated by western blot. Cox proportional hazard model and log-rank test were used to determine the prognostic potential of these proteins. High pigmentation was seen in 67% of the UM cases. The expression of HERC2 and P-protein was present in 44% and 71% cases, respectively. On statistical analysis, increased pigmentation, epithelioid cell type, and ciliary body invasion were significant with the protein expressions (p < 0.05). Metastasis-free survival was reduced in UM cases which expressed HERC2 and P-protein. On multivariate analysis, P-protein expression was found to be an independent prognostic factor. Our findings suggest that HERC2 and P-protein could be used as novel predictors of high pigmentation in UM cases which have high metastatic potential.

Current Molecular Markers of Melanoma and Treatment Targets

Melanoma is a deadly skin cancer that becomes especially difficult to treat after it metastasizes. Timely identification of melanoma is critical for effective therapy, but histopathologic diagnosis can frequently pose a significant challenge to this goal. Therefore, auxiliary diagnostic tools are imperative to facilitating prompt recognition of malignant lesions. Melanoma develops as result of a number of genetic mutations, with UV radiation often acting as a mutagenic risk factor. Novel methods of genetic testing have improved detection of these molecular alterations, which subsequently revealed important information for diagnosis and prognosis. Rapid detection of genetic alterations is also significant for choosing appropriate treatment and developing targeted therapies for melanoma. This review will delve into the understanding of various mutations and the implications they may pose for clinical decision making.

Rate of diagnostic errors and serious misdiagnosis-related harms for major vascular events, infections, and cancers: toward a national incidence estimate using the “Big Three”

Background

Missed vascular events, infections, and cancers account for ~75% of serious harms from diagnostic errors. Just 15 diseases from these “Big Three” categories account for nearly half of all serious misdiagnosis-related harms in malpractice claims. As part of a larger project estimating total US burden of serious misdiagnosis-related harms, we performed a focused literature review to measure diagnostic error and harm rates for these 15 conditions.

Methods

We searched PubMed, Google, and cited references. For errors, we selected high-quality, modern, US-based studies, if available, and best available evidence otherwise. For harms, we used literature-based estimates of the generic (disease-agnostic) rate of serious harms (morbidity/mortality) per diagnostic error and applied claims-based severity weights to construct disease-specific rates. Results were validated via expert review and comparison to prior literature that used different methods. We used Monte Carlo analysis to construct probabilistic plausible ranges (PPRs) around estimates.

Results

Rates for the 15 diseases were drawn from 28 published studies representing 91,755 patients. Diagnostic error (false negative) rates ranged from 2.2% (myocardial infarction) to 62.1% (spinal abscess), with a median of 13.6% [interquartile range (IQR) 9.2–24.7] and an aggregate mean of 9.7% (PPR 8.2–12.3). Serious misdiagnosis-related harm rates per incident disease case ranged from 1.2% (myocardial infarction) to 35.6% (spinal abscess), with a median of 5.5% (IQR 4.6–13.6) and an aggregate mean of 5.2% (PPR 4.5–6.7). Rates were considered face valid by domain experts and consistent with prior literature reports.

Conclusions

Diagnostic improvement initiatives should focus on dangerous conditions with higher diagnostic error and misdiagnosis-related harm rates.

Malignant melanoma of the breast: controversies in the diagnosis and therapeutic management of a rare nosologic entity

Melanoma of the breast is an infrequent entity, presenting as either primary or metastatic from extramammary solid neoplasms. Depending on the involvement of the skin, primary malignant melanoma of the breast (PMMB) can be classified as cutaneous or noncutaneous. Cutaneous PMMB accounts for <5% of all melanomas and only 0.5% of all breast cancers. Furthermore, despite the rarity of metastatic breast neoplasms, melanoma comprises a frequent source of metastases. Metastatic potential of melanoma is associated with poor prognosis, and the majority of patients present more than one metastatic foci at the time of diagnosis. Diagnostic approach for both primary and metastatic melanomas of the breast is substantiated by fine needle aspiration (FNA) cytology along with immunohistochemistry. Nevertheless, verification of a metastatic mammary melanoma requires the discovery of a primary lesion. The mainstay of treatment for primary tumors is surgery, with radical local excision and axillary lymph node dissection or, on occasion, axillary sentinel node resection, while for metastatic tumors it depends on the specificities of the melanoma. Adjuvant therapy is always implemented. The aim of this survey is to meticulously review the literature of primary and metastatic malignant melanomas of the breast and report epidemiologic and clinicopathologic data for this rare entity. Clinical features, histogenesis, morphological, and immunochemical findings are discussed, while the role of current diagnostic and therapeutic management of this uncommon entity is emphasized.

Recognising Skin Cancer in Primary Care

Skin cancer, including melanoma, basal cell carcinoma and cutaneous squamous cell carcinoma, has one of the highest global incidences of any form of cancer. In 2016 more than 16,000 people were diagnosed with melanoma in the UK. Over the last decade the incidence of melanoma has increased by 50% in the UK, and about one in ten melanomas are diagnosed at a late stage. Among the keratinocyte carcinomas (previously known as non-melanoma skin cancers), basal cell carcinoma is the most common cancer amongst Caucasian populations. The main risk factor for all skin cancer is exposure to ultraviolet radiation-more than 80% are considered preventable. Primary care clinicians have a vital role to play in detecting and managing patients with skin lesions suspected to be skin cancer, as timely diagnosis and treatment can improve patient outcomes, particularly for melanoma. However, detecting skin cancer can be challenging, as common non-malignant skin lesions such as seborrhoeic keratoses share features with less common skin cancers. Given that more than 80% of skin cancers are attributed to ultraviolet (UV) exposure, primary care clinicians can also play an important role in skin cancer prevention. This article is one of a series discussing cancer prevention and detection in primary care. Here we focus on the most common types of skin cancer: melanoma, squamous cell carcinoma and basal cell carcinoma. We describe the main risk factors and prevention advice. We summarise key guidance on the symptoms and signs of skin cancers and their management, including their initial assessment and referral. In addition, we review emerging technologies and diagnostic aids which may become available for use in primary care in the near future, to aid the triage of suspicious skin lesions.

Morpho-Molecular Assessment Indicates New Prognostic Aspects and Personalized Therapeutic Options in Sinonasal Melanoma

Sinonasal melanoma is a rare subtype of melanoma and little is known about its molecular fingerprint. Systemic treatment options are limited, as targetable BRAF mutations are rare compared to cutaneous melanoma. Currently, metastatic sinonasal melanoma is being treated according to the guidelines of cutaneous melanoma. In this study, we investigated the molecular profile of 19 primary sinonasal melanomas, using a novel customized melanoma-specific next generation sequencing (NGS) panel (MelArray) of 190 genes. Results were correlated to histological and clinical features to further characterize this rare, aggressive type of melanoma and screen for prognostic markers and possible treatment options. Molecular profiles encompassed predominantly mutations in NRAS (25%), whereas KIT or BRAF p.V600 mutations were not detected. Tumor mutational burden was overall low. High level of copy number variations (CNVs) were associated with alterations in DNA-repair genes and shorter distant metastasis-free survival (p = 0.005). Monomorphic (vs. pleomorphic) morphology was found to be significantly associated with worse disease-specific survival (p < 0.001), however no correlation between morphology and molecular aberrations was found. A variety of alterations in different pathways were detected, justifying molecular testing and opening potential personalized treatment options in current study or compassionate use settings.

Amelanotic Acral Lentiginous Melanoma of the Heel: A Case Report of Misdiagnosis

Acral lentiginous melanoma is an uncommon skin cancer that usually affects palms, soles, and nail apparatus of elderly Black and Asian individuals. Diagnosis is difficult, as it may mimic benign or traumatic lesions such as plantar warts or diabetic ulcers, especially if it is amelanotic. For this reason, detection is challenging, and proper diagnosis and treatment is often delayed, ultimately resulting in a poor prognosis. We report an 83-year-old Hispanic female with a two-year history of a painful, non-healing, glistening, exophytic mass on her left heel that was previously treated as a wart prior to proper biopsy and management. Patient education, complete physical exam and greater knowledge about this tumor, whether pigmented or not, are an important weapon to prevent its aggressiveness, increasing patients’ survival rate by decreasing the risk local invasion and metastasis. Biopsy should always be considered, especially in the setting of unresponsiveness to the treatment.

Mcl-1 Inhibitor Induces Cells Death in BRAF-Mutant Amelanotic Melanoma Trough GSH Depletion, DNA Damage and Cell Cycle Changes

Mcl-1 is a potent antiapoptotic protein and amplifies frequently in many human cancer. Currently, it is considered that the extensively expressed of Mcl-1 protein in melanoma cells is associated with rapid tumor progression, poor prognosis and low chemosensitivity. Therefore, the antiapoptotic protein Mcl-1 could be considered as a potential target for malignant melanoma treatment. The aim of this study was to assess the effect of MIM1 a specific low molecular Mcl-1 protein inhibitor and mixture of MIM1 and dacarbazine on the viability, cell cycle progression and apoptosis induction in amelanotic C32 melanoma cells. The cytotoxic activity of MIM1 towards C32 melanoma cells was examined by the WST-1 test. The Mcl-1 protein level as a drug target in amelanotic melanoma cells was defined by Western blot analysis. Cell cycle progression, DNA fragmentation as well as GSH depletion were determined by fluorescence image cytometer NucleoCounter NC-3000. The obtained results demonstrate that the specific Mcl-1 protein inhibitor - MIM1 decreases cell viability and induce apoptosis (S-phase arrest, DNA fragmentation and redox imbalance) in amelanotic melanoma cells and intensify the proapoptotic properties of DTIC, as a result of interactions with Mcl-1 protein. Taken together, the presented data suggest that Mcl-1 protein is a an important target in malignant melanoma treatment and provide for the first time convincing evidence that MIM1, which inhibits Mcl-1 antiapoptotic protein is able to induce apoptosis and sensitize melanoma cells to alkylating agent.

Characteristics of melanoma in white and nonwhite children, adolescents, and young adults: Analysis of a pediatric melanoma institutional registry, 1995-2018

OBJECTIVES

To characterize clinical differences among nonwhite/multiethnic vs white children, adolescents, and young adults with melanoma or atypical melanocytic neoplasms, including atypical Spitz tumors.

PATIENTS AND METHODS

A cohort of 55 patients (< 25 years of age) prospectively followed from 1995 to 2018 in the Stanford Pigmented Lesion and Melanoma Program was analyzed for differences in clinical presentation, including skin phototype, race/ethnicity, age, sex, tumor/melanoma characteristics, and outcome.

RESULTS

Seventeen patients (9 males and 8 females) were classified as nonwhite (predominantly skin phototype IV) and of Hispanic, Asian, or Black/African American ethnicity, and 38 patients (21 males and 17 females) were classified as white (predominantly phototypes I/II). Ages ranged from 6 months to 24 years, and median follow-up was 36 months (range 1-180 months). Melanomas were diagnosed in 87% of whites in our cohort, compared to 65% of nonwhites, with the remainder representing mainly atypical Spitz tumors. Lesions were usually brought to the attention of a health care provider by the patient or family (P < 0.05). Compared with whites, nonwhites were more likely to present at a younger mean age (10.9 years vs 15.4 years, P < 0.05) and with pink/clinically amelanotic tumors (59% vs 24%, P = 0.02).

CONCLUSIONS

This long-term prospective institutional study showed clinically relevant differences between nonwhite vs white children, adolescents, and young adults diagnosed with melanoma and atypical melanocytic neoplasms. Nonwhite patients presented at a younger age and had more clinically amelanotic melanocytic tumors. Increased recognition of clinical factors and risk of these tumors in nonwhites could result in earlier diagnosis.

Melanin presence inhibits melanoma cell spread in mice in a unique mechanical fashion

Melanoma is a highly aggressive cancer that exhibits metastasis to various critical organs. Unlike any other cancer cells, melanoma cells can synthesize melanin in large amounts, becoming heavily pigmented. Until now the role of melanin in melanoma, particularly the effect of melanin presence on the abilities of melanoma cells to spread and metastasize remains unknown. Recently, we have shown that melanin dramatically modified elastic properties of melanoma cells and inhibited the cells invasive abilities in vitro. Here, we inoculated human melanoma cells with different melanin content into nude mice and tested the hypothesis that cell elasticity is an important property of cancer cells for their efficient spread in vivo. The obtained results clearly showed that cells containing melanin were less capable to spread in mice than cells without the pigment. Our findings indicate that the presence of melanin inhibits melanoma metastasis, emphasizing possible clinical implications of such an inhibitory effect.

Multiple synchronous anorectal melanomas with different colors: A case report

BACKGROUND

Anorectal melanoma (AM) is an extremely rare malignant tumor originating from anorectal melanocytes with a poor prognosis. AM has been reported to have a much lower incidence than cutaneous or choroid melanoma, accounting for 0.4%-1.6% of all melanomas.

CASE SUMMARY

We report a 76-year-old female patient diagnosed with anorectal malignant melanoma by colonoscopy and biopsy. Intraoperative examination revealed two distinct anorectal tumors, one melanotic and another amelanotic, as well as two pigmented mucosal zones at the dentate line level. Abdominal perineal resection was performed. A pathological report confirmed all four lesions to be melanomas. Postoperatively, we followed an immunotherapy protocol targeting PD-1 (nivolumab). The patient had 24 mo of disease-free follow-up upon completion of nivolumab treatment.

CONCLUSION

This is the first reported case presenting coexistence of pigmented and unpigmented AMs in the same patient.

Antimelanoma activity of perphenazine and prochlorperazine in human COLO829 and C32 cell lines

Cutaneous melanoma is least common (only about 1% of skin cancers) but is the deadliest malignant tumor. Moreover, amelanotic types of melanoma are very difficult for clinical diagnosis. The standard therapy can cause a lot of side effects, e.g., nausea, vomiting, and headaches, which means that novel and effective strategies are required. Interestingly, phenothiazine derivatives possess sedative, antiemetic, and anticancer activity. Our goal was to determine the effect of perphenazine and prochlorperazine on cell viability, motility, microphthalmia-associated transcription factor (MITF) and tyrosinase content in melanotic and amelanotic melanoma cells. The viability of C32 and COLO829 melanoma cells was evaluated by the WST-1 colorimetric assay; impact on motility of human melanoma was performed by wound-healing assay, while tyrosinase and MITF content were determined by Western blot. In the present study, we explore the anticancer effect of perphenazine and prochlorperazine in human melanotic (COLO829) and amelanotic (C32) melanoma cells concluding that prochlorperazine inhibits cell viability in a concentration-dependent manner, impairs motility, and decreases tyrosinase and MITF amounts. Moreover, the analyzed drugs decrease/increase MITF amount depending on the type of melanoma. We demonstrated that the decrease of MITF and tyrosinase protein induces motility inhibition of C32 cells, which suggests the ability of those drugs to restore cancer cell sensitivity to treatment. The ability of prochlorperazine to contain the spread of the amelanotic melanoma in vivo may be helpful in the development of a new and effective antimelanoma therapies.

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.

Recurrent amelanotic melanoma of nasal cavity: Biological variability and unpredictable behavior of mucosal melanoma. A case report

The aim of this report is to present a case of a patient with a recurrent nasal cavity amelanotic melanoma (AM), with emphasis on diagnosis and therapy options of this clinical entity. A 65-year-old female patient presented with pain in the right cheek region and nasal obstruction. In 2013, she was diagnosed with mucosal melanoma (MM) of the left nasal cavity. After endoscopic surgery and radiotherapy, the patient was followed by the oncology team. Five years after the initial diagnosis, rhinoscopy showed a tumorous formation in the right nasal cavity. The tumor mass was without black discoloration and was the same color as the surrounding nasal mucosa. Microscopic examination after biopsy of the tumor confirmed amelanotic MM. The patient underwent an additional endoscopic surgery. A complete standard diagnostic workup for MM found metastases in head and neck lymph nodes, on both sides. MMs of head and neck are uncommon malignancies. Unique biology of MM cells causes a high rate of recurrences. This report presents an example of recurrent AM of the nasal cavity, in treatment with checkpoint inhibitor (pembrolizumab), which could provide a good therapy option for patients with MM.

Malignant melanoma clinically mimicking pyogenic granuloma: comparison of clinical evaluation and histopathology

Amelanotic melanomas (AMMs) account for a small proportion of all melanomas. They pose a risk of delayed diagnosis and, consequently, poor prognosis. AMMs may atypically present as a pyogenic granuloma-like lesion. This study sought to investigate the prevalence and clinical and histological features of AMM masquerading as pyogenic granuloma. The database of a tertiary medical center was screened for all patients pathologically diagnosed with melanoma in 2005-2016. Those with a suspected primary (i.e. pre-excision) clinical diagnosis of pyogenic granuloma were identified, and their demographic, clinical, histologic, and outcome data were collected from the medical files. Of 2038 patients diagnosed with melanoma, 10 (∼0.5%) had a pyogenic granuloma-like AMM. The mean±SD age at lesion presentation was 56±18.9 years and the mean time from lesion appearance to diagnosis was 91.5±117.1 months. Nine tumors were located on the skin surface, and one on the oral mucosa. The mean lesion size was 19.6±14.1 mm and the mean Breslow's depth was 6.47±3.1 mm; all tumors presented in the vertical growth phase. Seven (70%) patients had lymph node involvement or metastasis at diagnosis. Two patients died of the disease within 1 year of diagnosis. Given the potential lethality of AMM and the benign nature of pyogenic granuloma, clinician recognition of pyogenic granuloma-like AMMs is crucial. In the presence of a pyogenic granuloma-like lesion, findings of older patient age and large tumor size should raise the index of suspicion and prompt a biopsy study, thereby ensuring early and accurate treatment.

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.

Amelanotic acral melanoma misdiagnosed as verruca plantaris

We report a case of amelanotic acral melanoma in a 42-year-old Chinese woman. Ten months previously the patient found a 2-cm asymmetric erythematous macular plaque on her left sole. The lesion was diagnosed as verruca plantaris by every physician the patient consulted. One month ago, an enlarged lymph node was detected in the left groin, which biopsy reported as metastatic melanoma. Dermoscopy suggested verruca plantaris, and positron emission tomography (PET) revealed increased glucose metabolism in the macular plaque. Finally, biopsy of the plaque revealed amelanotic melanoma. Misdiagnosis and diagnostic delay are usually associated with poorer patient outcomes. Awareness of atypical presentations of acral melanoma is thus important for decreasing misdiagnosis rates and improving patient outcomes.

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.