Development Of Primary Melanoma Research Articles

Innate Lymphoid Cells in the Malignant Melanoma Microenvironment.

Simple SummaryInnate lymphoid cells (ILCs) are the innate counterparts of adaptive immune cells. Emerging data indicate that they are also key players in the progression of multiple tumors. In this review we briefly describe ILCs’ functions in the skin, lungs and liver. Next, we analyze the role of ILCs in primary cutaneous melanoma and in its most frequent and deadly metastases, those in liver and lung. We focus on their dual anti– and pro-tumoral functions, depending on the cross-interactions among them and with the surrounding stromal cells that form the tumor microenvironment (TME) in each organ. Next, we detail the role of extracellular vesicles secreted to the TME by ILCs and melanoma on both cell populations. We conclude that the identification of markers and tools to allow the modulation of individual ILC subsets, in addition to the development of standardized protocols, is essential for addressing the therapeutic modulation of ILCs.The role of innate lymphoid cells (ILCs) in cancer progression has been uncovered in recent years. ILCs are classified as Type 1, Type 2, and Type 3 ILCs, which are characterized by the transcription factors necessary for their development and the cytokines and chemokines they produce. ILCs are a highly heterogeneous cell population, showing both anti– and protumoral properties and capable of adapting their phenotypes and functions depending on the signals they receive from their surrounding environment. ILCs are considered the innate counterparts of the adaptive immune cells during physiological and pathological processes, including cancer, and as such, ILC subsets reflect different types of T cells. In cancer, each ILC subset plays a crucial role, not only in innate immunity but also as regulators of the tumor microenvironment. ILCs’ interplay with other immune and stromal cells in the metastatic microenvironment further dictates and influences this dichotomy, further strengthening the seed-and-soil theory and supporting the formation of more suitable and organ-specific metastatic environments. Here, we review the present knowledge on the different ILC subsets, focusing on their interplay with components of the tumor environment during the development of primary melanoma as well as on metastatic progression to organs, such as the liver or lung.

Reexamining the Threshold for Reexcision of Histologically Transected Dysplastic Nevi

Controversy persists regarding the appropriate management of incompletely excised, biopsy-proven, mild and moderate dysplastic nevi (DN). To determine long-term risk of associated melanoma in biopsied mild or moderate DN with positive histologic margins that were clinically observed vs reexcised with negative margins. Retrospective cohort study of mixed referral and community patients from an academic pigmented lesion clinic and dermatology clinics of the affiliated Veteran Affairs medical center with biopsy-confirmed DN with positive histologic margins diagnosed from May 15, 1991, to July 8, 2015, and followed up through May 30, 2016. A consecutive sample of 1473 histologically confirmed DN was identified using surgical pathology databases at the study sites; 590 cases in 498 patients met eligibility criteria. The primary outcome was the proportion of biopsied DN that progressed to histologically confirmed invasive or in situ melanoma. Secondary outcomes included local nevus recurrence and development of primary melanoma at other anatomic sites. The 498 patients had a mean (range) age of 57.6 (14-93) years and 90% were male. Among 590 positive-margin DN, 191 were reexcised and 399 clinically observed without further surgery; 170 reexcised and 304 observed DN had available follow-up data, with mean (SD) follow-up of 5.5 (4.6) years. Cases in the observation group were more likely to demonstrate nevus recurrence than those that were reexcised (3.3% vs 0%; P = .02). Six of 304 (2.0%) observed DN subsequently developed melanoma at the same site, compared with 1 of 170 (0.06%) that were reexcised (P = .43). Five of 6 observed patients who developed melanoma initially underwent partial biopsy with grossly positive margins; 1 melanoma in situ evolved from an excisionally biopsied moderately dysplastic nevus 5 years later. Only 1 case of thin invasive melanoma (≤1 mm) was observed, and no deaths from melanoma arising from biopsy-proven DN occurred through the latest dermatology follow-up. New primary melanoma developed at other sites in 9.9% of excised and 9.4% of resected DN. In cases of mild and moderate DN with microscopically positive margins and no concerning clinical residual lesion, observation, rather than reexcision, was a reasonable management option. Partial biopsies of pigmented lesions suspicious for melanoma may lead to delayed melanoma diagnosis and should be discouraged.

Molecular pathway activation features linked with transition from normal skin to primary and metastatic melanomas in human.

Melanoma is the most aggressive and dangerous type of skin cancer, but its molecular mechanisms remain largely unclear. For transcriptomic data of 478 primary and metastatic melanoma, nevi and normal skin samples, we performed high-throughput analysis of intracellular molecular networks including 592 signaling and metabolic pathways. We showed that at the molecular pathway level, the formation of nevi largely resembles transition from normal skin to primary melanoma. Using a combination of bioinformatic machine learning algorithms, we identified 44 characteristic signaling and metabolic pathways connected with the formation of nevi, development of primary melanoma, and its metastases. We created a model describing formation and progression of melanoma at the level of molecular pathway activation. We discovered six novel associations between activation of metabolic molecular pathways and progression of melanoma: for allopregnanolone biosynthesis, L-carnitine biosynthesis, zymosterol biosynthesis (inhibited in melanoma), fructose 2, 6-bisphosphate synthesis and dephosphorylation, resolvin D biosynthesis (activated in melanoma), D-myo-inositol hexakisphosphate biosynthesis (activated in primary, inhibited in metastatic melanoma). Finally, we discovered fourteen tightly coordinated functional clusters of molecular pathways. This study helps to decode molecular mechanisms underlying the development of melanoma.

Dividing and conquering: controlling advanced melanoma by targeting oncogene-defined subsets

For decades, therapy for advanced melanoma has lagged behind most of the cancer field owing to its intrinsic resistance to conventional cytotoxic chemotherapy and limited impact of cytokine-based immunotherapy. The opportunity to develop molecularly targeted therapy emerged with the discovery of activating mutations in BRAF, a component of the long studied MAP kinase pathway. These mutations are found in approximately 50 % of patients with regionally advanced or metastatic melanoma and appear to be one of the initiating steps in the development of primary melanoma. Additional oncogenic events, particularly those that affect tumor suppressor genes, are essential for development of invasive and metastatic melanoma. Nonetheless, mutated BRAF retains its central contribution to melanoma pathophysiology even in advanced stage disease as manifested by the remarkable antitumor effects and alteration the natural history of metastatic melanoma of selective BRAF inhibitors. After initial response, resistance commonly emerges within a few months' time and the field has focused on delineating molecular mechanisms of resistance toward the goal of improving upon the early therapeutic effects of single agent BRAF inhibition. Combination regimens are currently undergoing clinical investigation. NRAS and CKIT mutant melanoma represent the next oncogene defined melanoma subsets for which initial targeted therapy approaches are being explored, with early evidence suggesting progress with MEK and CKIT inhibitors, respectively. A considerable subset of patients have melanomas that are not defined by the presence of BRAF, NRAS, or CKIT mutations and, thus, the elucidation of the entire melanoma genome is being pursued with the hope of identifying additional therapeutic targets.