Differential histone acetylation and super-enhancer regulation underlie melanoma cell dedifferentiation.

Dedifferentiation or phenotype switching refers to the transition from a proliferative to an invasive cellular state. We previously identified a 122-gene epigenetic gene signature that classifies primary melanomas as low versus high risk (denoted as Epgn1 or Epgn3). We found that the transcriptomes of the Epgn1 low-risk and Epgn3 high-risk cells are similar to the proliferative and invasive cellular states, respectively. These signatures were further validated in melanoma tumor samples. Examination of the chromatin landscape revealed differential H3K27 acetylation in the Epgn1 low-risk versus Epgn3 high-risk cell lines that corroborated with a differential super-enhancer and enhancer landscape. Melanocytic lineage genes (MITF, its targets and regulators) were associated with super-enhancers in the Epgn1 low-risk state, whereas invasiveness genes were linked with Epgn3 high-risk status. We identified the ITGA3 gene as marked by a super-enhancer element in the Epgn3 invasive cells. Silencing of ITGA3 enhanced invasiveness in both in vitro and in vivo systems, suggesting it as a negative regulator of invasion. In conclusion, we define chromatin landscape changes associated with Epgn1/Epgn3 and phenotype switching during early steps of melanoma progression that regulate transcriptional reprogramming. This super-enhancer and enhancer-driven epigenetic regulatory mechanism resulting in major changes in the transcriptome could be important in future therapeutic targeting efforts.

B7-H3 drives immunosuppression and Co-targeting with CD47 is a new therapeutic strategy in ß-catenin activated melanomas.

In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T-cell non-inflamed tumors (cold tumors) are associated with tumor cell-intrinsic Wnt/ß-catenin activation, and are typically resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the 'cold tumor' phenotype and identifying new effective immunotherapies are challenges. We sought to investigate the role of a newer immunotherapy agent, B7-H3, in this setting. RNA sequencing was used to identify co-targeting strategies upon B7-H3 inhibition in a well-defined preclinical melanoma model driven by ß-catenin. We found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and innate immunity. B7-H3 inhibition led to an inflamed microenvironment, up-regulation of CD47/SIRPa signaling, and together with blockade of the macrophage checkpoint CD47 resulted in additive antitumor responses. We found that the antitumor effects of the B7-H3/CD47 antibody combination were dependent on cytokine signaling pathways (CCR5/CCL5 and IL4).

Early Fractional Ablative Laser for Skin Cancer Excision Scars: A Randomized Split-Scar Study.

BACKGROUND: Fractional ablative laser resurfacing has been shown to improve the final cosmetic appearance of surgical scars, but optimal timing is unknown. OBJECTIVE: To compare surgical scars treated with fractional carbon dioxide (CO 2 ) laser performed on Day 0 and Day 14. METHODS: Prospective, randomized, split-scar, physician-blinded study of 30 surgical scars on the limbs. Scars halves received fractional CO 2 laser on either Day 0 or Day 14. Scar assessment at 6 months evaluated patient preference, physician modified Manchester Scar Scale (MMSS) score, and quantitative scar analysis on histology (fractal dimension [F D ] and lacunarity [L] analysis). RESULTS: There was no significant difference in patient assessment (54% preferred Day 0 side, 46% preferred Day 14 side, p = .58) or physician assessment (mean MMSS 8.4 for Day 0 vs 8.7 for Day 14, p = .28). Fractal dimensions were similar for both interventions (mean 1.778 for Day 0 vs 1.781 for Day 14, p = .80). Lacunarity was similar for both interventions (mean 0.368 for Day 0 vs 0.345 for Day 14, p = .44). LIMITATIONS: Single-center study with wounds limited to limbs of skin Phototype I-II subjects; 4 of whom were lost to follow-up. CONCLUSION: Intraoperative CO 2 laser is noninferior to Day 14 laser resurfacing for surgical scar treatment.

A nuclear cAMP microdomain suppresses tumor growth by Hippo pathway inactivation.

Cyclic AMP (cAMP) signaling is localized to multiple spatially distinct microdomains, but the role of cAMP microdomains in cancer cell biology is poorly understood. Here, we present a tunable genetic system that allows us to activate cAMP signaling in specific microdomains. We uncover a nuclear cAMP microdomain that activates a tumor-suppressive pathway in a broad range of cancers by inhibiting YAP, a key effector protein of the Hippo pathway, inside the nucleus. We show that nuclear cAMP induces a LATS-dependent pathway leading to phosphorylation of nuclear YAP solely at serine 397 and export of YAP from the nucleus with no change in YAP protein stability. Thus, nuclear cAMP inhibition of nuclear YAP is distinct from other known mechanisms of Hippo regulation. Pharmacologic targeting of specific cAMP microdomains remains an untapped therapeutic approach for cancer; thus, drugs directed at the nuclear cAMP microdomain may provide avenues for the treatment of cancer.

Resolution of pembrolizumab-associated lichenoid dermatitis with a single dose of methotrexate.

We present a 53-year-old woman with severe lichenoid dermatitis secondary to pembrolizumab therapy that was refractory to both topical and oral steroids. After almost three months without improvement, the rash was effectively combated with a single 15mg dose of methotrexate. We hope this case will help guide the management of the cutaneous adverse effects of anti-PD1 immunotherapy.

Observational Study Examining the Diagnostic Practice of Ki67 Staining for Melanocytic Lesions.

BACKGROUND: Dermatopathologists routinely use Ki67 immunostaining to assess atypical melanocytic lesions with a dermal component to determine whether an ambiguous tumor is melanoma. However, there is no universal standard of use for Ki67 in melanocytic neoplasms. We sought to observe the real-world use of Ki67 in the diagnosis of melanocytic lesions and establish a best practice recommendation. METHODS: We searched dermatopathology reports from 2 academic practices for melanocytic lesions in which Ki67 staining was used for diagnosis. The proliferation rate was compared between cases diagnosed as benign (not requiring re-excision), moderate to severely dysplastic or atypical Spitz nevi (requiring re-excision), and malignant melanoma. The use of other melanocytic markers and consensus review was also recorded and compared between institutions. RESULTS: Pathology reports for 106 cases were reviewed. A high Ki67 proliferation rate (n = 18) favored a diagnosis of melanoma or nevi requiring re-excision (15/18, 83.3%) versus a benign nevus (3/18, 16.67%). A high Ki67 rate was 71.4%-90.9% sensitive and 40%-56% specific for the diagnosis of nevus requiring re-excision or melanoma. Institutional practices differed in regard to reporting of Ki67 staining, the use of multiple markers in the workup of atypical melanocytic lesions (HMB45, Melan-A, Ki67 being most common), and consensus review. CONCLUSIONS: A negative or low Ki67 proliferation rate correlates well with rendering of a benign diagnosis. However, a low proliferation rate does not preclude the diagnosis of melanoma. Ki67 staining is most commonly used as an ancillary test to support a diagnosis after other factors have been considered, such as histopathologic morphology and results of additional concurrently used stains.

Distinguishing pustular psoriasis and acute generalized exanthematous pustulosis on the basis of plasmacytoid dendritic cells and MxA protein.

BACKGROUND: Distinguishing acute generalized exanthematous pustulosis (AGEP) and pustular psoriasis (PS) can be challenging. Staining for plasmacytoid dendritic cells, or PDCs (producer of IFN-α/ß), and MxA (an IFN-α/ß inducible protein) may help discriminate these entities. METHODS: Forty-three cases of AGEP and PS were compiled from two academic institutions. All cases were examined for CD123+ PDCs, eosinophils, acanthosis, papillomatosis, suprapapillary plate thinning, tortuous dilated capillaries, single necrotic keratinocytes, papillary dermal edema, vasculitis, eosinophil exocytosis, intraepidermal pustules, and subcorneal pustules. A subset of cases (n = 26) was stained for MxA. RESULTS: Perivascular and intraepidermal PDCs, dilated tortuous vessels, and MxA expression in the dermal inflammatory infiltrate were significantly (P < 0.05) in favor of a diagnosis of PS. The absence of PDCs and presence of eosinophils favored a diagnosis of AGEP (P < 0.05). CONCLUSIONS: We found compelling evidence for the use of CD123 to highlight PDCs in these cases. The presence of PDCs and expression of MxA in dermal inflammatory infiltrate, as well as absence of eosinophils and presence of tortuous dilated capillaries favored a diagnosis of PS. Expression of MxA in the dermal infiltrate corresponds with a Th1 pathway in PS and may indicate a Th1 component in the early initial phase of AGEP.

The Misdiagnosis of Acral Lentiginous Melanoma: Three Case Presentations.

Acral lentiginous melanoma (ALM) is a disease that is found on the palms, soles, and nail beds. Because these areas are not often examined during general medical examinations, the presence of ALM often goes unnoticed or the diagnosis is delayed. Research shows that the misdiagnosis of ALM is common, reported between 20% and 34%. We present three cases of ALM that were initially misdiagnosed and referred to the senior author (B.C.M.) in an effort to assess why misdiagnosis is common. The existing literature illuminates clinical pitfalls in diagnosing ALM. The differential diagnosis of many different podiatric skin and nail disorders should include ALM. Although making the correct diagnosis is essential, the prognosis is affected by the duration of the disease and level of invasiveness. Unfortunately, most of the reported misdiagnosed cases are of a later stage and worse prognosis. This review highlights that foot and ankle specialists should meet suspect lesions with a heightened index of suspicion and perform biopsy when acral nonhealing wounds and/or lesions are nonresponsive to treatment.

Cutaneous/subcutaneous mesenchymal proliferations of the breast.

Cutaneous mesenchymal "spindle cell" lesions arising in the vicinity of the breast represent a complex clinical and diagnostic scenario which may overlap histopathologically and immunohistochemically with mammary spindle cell proliferations, potentially impacting management and overall prognostication. In this review, we suggest a pattern-based approach to assist in the evaluation of these lesions. A comprehensive description of each entity is accompanied by a cutaneous and mammary differential diagnosis.

Giant benign intradermal melanocytic nevus of rapid onset.

Benign melanocytic nevi are slowly growing acquiredor congenital tumors with varied morphology,commonly encountered in dermatology clinics. Anytumor with rapid clinical growth must be assessedcarefully in order to exclude malignancy. We report awoman with a histopathologically benign intradermalnevus that presented as a rapidly evolving largecutaneous mass on the ear. Owing to the discrepancybetween the clinical and histopathological findings,an extensive histopathological work-up involvingmany deeper sections, immunohistochemical stains,and fluorescent in situ hybridization (FISH) analysiswas conducted in order to rule out malignancy.

Squamous cell carcinoma with enteric adenocarcinomatous differentiation.

We report a highly unusual case of a primary cutaneous squamous cell carcinoma (SCC) with intermixed enteric-type adenocarcinomatous dedifferentiation and a small component of undifferentiated mesenchymal differentiation. We believe this is the first time this form of phenotypic plasticity has been described in cutaneous SCC.

The metabolic/pH sensor soluble adenylyl cyclase is a tumor suppressor protein.

cAMP signaling pathways can both stimulate and inhibit the development of cancer; however, the sources of cAMP important for tumorigenesis remain poorly understood. Soluble adenylyl cyclase (sAC) is a non-canonical, evolutionarily conserved, nutrient- and pH-sensing source of cAMP. sAC has been implicated in the metastatic potential of certain cancers, and it is differentially localized in human cancers as compared to benign tissues. We now show that sAC expression is reduced in many human cancers. Loss of sAC increases cellular transformation in vitro and malignant progression in vivo. These data identify the metabolic/pH sensor soluble adenylyl cyclase as a previously unappreciated tumor suppressor protein.

Microcystic Adnexal Carcinoma of the scalp in an african-american male.

Microcystic adnexal carcinoma (MAC) is a rare adnexal neoplasm that typically presents in Caucasians. We report a rare case of MAC in a 68 year old African American male that presented as a large asymptomatic scalp mass. The clinical and histologic features of MAC are discussed. A summary of all reported cases of MAC in African American patients is presented, and treatment options are discussed.

Post-radiation atypical vascular proliferation on the head of a young woman: a diagnostic challenge.

With improved outcomes associated with radiotherapy (RT), post-irradiation tumors are increasingly seen in long-term cancer survivors. We report a case of a young woman who presented with a three-year history of a vascular lesion on the temple, previously irradiated for a childhood brain tumor. The history of radiation, the clinical appearance, and the biopsy findings of an atypical vascular proliferation in the dermis, were worrisome for a malignant vascular neoplasm and prompted surgical excision. However, further tissue analysis of the excised specimen confirmed a benign atypical vascular lesion (AVL) overlying a banal pilar cyst. Distinguishing post-radiation benign from malignant vascular lesions can be difficult because they share overlapping clinical and histopathologic features. Thus, any vascular lesion that occurs in a previously irradiated field should be excised completely with tumor-free margins and examined histologically.

Investigation of cAMP microdomains as a path to novel cancer diagnostics.

Understanding of cAMP signaling has greatly improved over the past decade. The advent of live cell imaging techniques and more specific pharmacologic modulators has led to an improved understanding of the intricacies by which cAMP is able to modulate such a wide variety of cellular pathways. It is now appreciated that cAMP is able to activate multiple effector proteins at distinct areas in the cell leading to the activation of very different downstream targets. The investigation of signaling proteins in cancer is a common route to the development of diagnostic tools, prognostic tools, and/or therapeutic targets, and in this review we highlight how investigation of cAMP signaling microdomains driven by the soluble adenylyl cyclase in different cancers has led to the development of a novel cancer biomarker. Antibodies directed against the soluble adenylyl cyclase (sAC) are highly specific markers for melanoma especially for lentigo maligna melanoma and are being described as "second generation" cancer diagnostics, which are diagnostics that determine the 'state' of a cell and not just identify the cell type. Due to the wide presence of cAMP signaling pathways in cancer, we predict that further investigation of both sAC and other cAMP microdomains will lead to additional cancer biomarkers. This article is part of a Special Issue entitled: The role of soluble adenylyl cyclase in health and disease.

Neighboring look-a-likes: distinguishing between breast and dermatologic lesions.

Due to the proximity of the skin, subcutis, and axilla to the breast, the possibility of a "breast mass" actually representing a dermatologic lesion should be considered, particularly if the proliferation does not look characteristically "mammary" in appearance. Even more underappreciated is the scenario of a dermatologic proliferation morphologically masquerading as a breast tumor. The pathologist can fall prey to this pitfall if he/she is led to believe that the location of the tumor is the breast proper. The aim of this review is to provide an overview of dermatologic mimickers of breast lesions and helpful ways to discern between them when possible.

Epidermotropic metastatic epithelioid sarcoma: a potential diagnostic pitfall.

Epithelioid sarcoma (ES) represents an aggressive soft tissue tumor with varied morphologic and histopathologic presentations that typically elicits a broad differential diagnosis, including granuloma annulare, necrobiotic granuloma, fibrous histiocytoma, synovial sarcoma, amelanotic melanoma and poorly differentiated primary cutaneous and metastatic adenocarcinoma. ES is characterized microscopically by a nodular arrangement of abundant, deeply eosinophilic, polygonal tumor cells with frequent central necrosis and hemorrhage, rare mitotic figures and minimal pleomorphism. At the periphery, tumor cells are spindle shaped and may exhibit frequent local infiltration along tendons, fascial planes and neurovascular bundles. Immunohistochemistry typically reveals expression of both epithelial and mesenchymal antigens, such as cytokeratin and vimentin, respectively. The absence of a connection between tumor cells and the overlying epidermis, with or without an in situ carcinoma component, typically rules out a primary cutaneous squamous cell carcinoma. We report a case of stage IV proximal-type ES that mimicked molluscum contagiosum clinically and was histopathologically reminiscent of invasive squamous cell carcinoma because of attachment and colonization of the overlying epidermis. The case represents an unusual pathologic presentation of ES and highlights potential pitfalls in establishing the diagnosis.