Melanoma is the deadliest form of skin cancer. In the early stages, melanoma can be treated successfully with surgery alone and survival rates are high, but after metastasis survival rates drop significantly. Therefore, early and correct diagnosis is key for ensuring patients have the best possible prognosis. Melanoma misdiagnosis accounts for more pathology and dermatology malpractice claims than any cancer other than breast cancer, as an early misdiagnosis can significantly reduce a patient’s chances of survival. As far as treatment for metastatic melanoma goes, there have been several new drugs developed over the last 10 years that have greatly improved the prognosis of patients with metastatic melanoma, however, a majority of patients do not show a lasting response to these treatments. Thus, new biomarkers and drug targets are needed to improve the accuracy of melanoma diagnosis and treatment. This article will discuss the major advancements of melanoma diagnosis and treatment from antiquity to the present day.

Shalin S C, Lyle S, Calonje E & Lazar A J F
(2010) Histopathology56, 133–147
Sebaceous neoplasia and the Muir–Torre syndrome: important connections with clinical implications Sebaceous neoplasia comprises a spectrum ranging from benign to malignant. Proper histological identification is important for treatment, prognosis and potential association with the Muir–Torre syndrome (MTS). Our increased understanding of the significance and pathogenesis of these tumours has led to improved risk stratification, screening recommendations, and treatment of patients with an initial presentation of a sebaceous tumour. This review focuses on the diagnostic and histological features of sebaceous lesions, the MTS, and recent insights into the molecular pathogenesis of sebaceous tumours.

The ERK/MAP kinase cascade is important for long-term memory formation and synaptic plasticity, with a myriad of upstream signals converging upon ERK activation. Despite this convergence of signaling, neurons routinely activate appropriate biological responses to different stimuli. Scaffolding proteins represent a mechanism to achieve compartmentalization of signaling and the appropriate targeting of ERK-dependent processes. We report that kinase suppressor of Ras (KSR1) functions biochemically in the hippocampus to scaffold the components of the ERK cascade, specifically regulating the cascade when a membrane fraction of ERK is activated via a PKC-dependent pathway but not via a cAMP/PKA-dependent pathway. Specificity of KSR1-dependent signaling also extends to specific downstream targets of ERK. Behaviorally and physiologically, we found that the absence of KSR1 leads to deficits in associative learning and theta burst stimulation-induced LTP. Our report provides novel insight into the endogenous scaffolding role of KSR1 in controlling kinase activation within the nervous system.

Modulation of the immune system can produce anti-tumor responses in various cancer types, including melanoma. Recently, immune checkpoint inhibitors (ICI), in single agent and combination regimens, have produced durable and long-lasting clinical responses in a subset of metastatic melanoma patients. These monoclonal antibodies, developed against CTLA-4 and PD-1, block immune-inhibitory receptors on activated T-cells, amplifying the immune response. However, even when using anti-CTLA-4 and anti-PD-1 in combination, approximately half of patients exhibit innate resistance and suffer from disease progression. Currently, it is impossible to predict therapeutic response. Here, we report the first proteomic and histone epigenetic analysis of patient metastatic melanoma tumors taken prior to checkpoint blockade, which revealed biological signatures that can stratify patients as responders or non-responders. Furthermore, our findings provide evidence of mesenchymal transition, a known mechanism of immune-escape, in non-responding melanoma tumors. We identified elevated histone H3 lysine (27) trimethylation (H3K27me3), decreased E-cadherin, and other protein features indicating a more mesenchymal phenotype in non-responding tumors. Our results have implications for checkpoint inhibitor therapy as patient specific responsiveness can be predicted through readily assayable proteins and histone epigenetic marks, and pathways activated in non-responders have been identified for therapeutic development to enhance responsiveness.

The extracellular signal-regulated kinase (ERK) cascade has received much attention for its possible role in neuronal synaptic plasticity. Although ERK activation has been linked to learning behaviors and activity-dependent neuronal function, much of the acquired data has relied upon pharmacological agents that suppress ERK function in both neurons and nonneuronal cells. To determine the function of neuronal ERK activity in learning, a new line of transgenic mice was generated wherein dominant-negative MEK1, the upstream obligate activator of ERK1/2, was expressed by using a neuronal-specific and pan-neuronal Talpha1 alpha-tubulin promoter element. Mice expressing this construct exhibited decreased ERK1/2 activity in the hippocampus and thus were tested for learning impairments. In a battery of control tests, including open field, rotarod, and shock threshold, the transgenic mice displayed no deficits and performed as well as their wild-type littermate counterparts. However, the mice displayed a significant impairment in contextual fear conditioning compared with the wild-type littermates. These findings indicate that the MEK1/ERK1/2 cascade within neurons plays an important role in the processes of learning and memory.

Identifying controlling features of responsiveness to checkpoint blockade therapies is an urgent goal in oncology research. Our group and others have previously shown melanoma tumors resistant to checkpoint blockade display features of mesenchymal transition, including E-cadherin loss. Here, we present the first in vivo evidence that E-cadherin from tumor cells facilitate immune attack, using a B16F10 melanoma mouse model in which E-cadherin is exogenously expressed (B16.Ecad). We find, compared with vector control, B16.Ecad exhibits delayed tumor growth, reduced metastatic potential, and increased overall survival in vivo. Transplantation of B16.Ecad into Rag1 À/À and CD103 À/À mice abrogated the tumor growth delay. This indicates the antimelanoma response against B16.Ecad is both immune and CD103 þ mediated. Moreover, B16.Ecad showed increased responsiveness to combination immune checkpoint blockade (ICB) compared with vector control. This work establishes a rationale for ICB responses observed in high E-cadherin-expressing tumors and suggests therapeutic advancement through amplifying CD103 þ immune cell subsets. Significance: These findings identify the mechanism behind checkpoint blockade resistance observed in melanoma that has undergone mesenchymal transition and suggest activation of CD103 þ immune cells as a therapeutic strategy against other E-cadherin-expressing malignancies.

Malignancy arising in association with endometriosis is a rare but well-documented phenomenon that was first described in the literature as early as 1925. Cutaneous endometriosis with subsequent malignant transformation is even more uncommon, and high clinical suspicion is required for diagnosis. The clinical differential diagnosis of these lesions includes a wide variety of entities, ranging from benign cysts to malignancies such as melanoma. We report a case of clear cell adenocarcinoma arising from endometriosis in a cesarean section scar in a 47-year-old woman, and we complete a review of the literature regarding this unusual entity.

Sebaceous neoplasms are commonly considered in their relationship to the Muir-Torre Syndrome and the now well-documented loss of DNA mismatch repair proteins leading to microsatellite instability. However, sebaceous neoplasms showing microsatellite instability comprise only a subset of this group of tumors, and thus alternative tumorigenic mechanisms must exist. This paper explores the relationship of p53, a tumor suppressor implicated in other cutaneous malignancies, and sebaceous neoplasia. We examined 94 sebaceous tumors from 92 patients. Tumors with strong nuclear p53 staining were significantly associated with the diagnosis of sebaceous carcinoma compared to benign sebaceous lesions, most notably for periocular carcinomas. Importantly, nuclear mismatch repair protein expression was intact in all lesions showing p53 alterations, suggesting that p53 dysfunction may represent a divergent pathway in the molecular pathogenesis of these tumors.