Acral Lentiginous Melanoma

High Copy Number Variations Correlate with a Pro-Tumoral Microenvironment and Worse Prognosis in Acral Lentiginous Melanoma

Acral lentiginous melanoma (ALM) is a rare melanoma subtype primarily located in acral regions. However, ALMs exhibit a distinctive genetic profile characterized by a high number of copy number variations (CNVs) and limited point mutations. Late diagnosis and restricted therapeutic efficacy contribute to its poor prognosis. The secretome within the tumor microenvironment (TME) influences immune modulation and plays a vital role in melanoma progression. We aim to analyze the role of ALM secretome and CNVs profile with prognosis in primary ALM patients. Here, we demonstrated that high CNV burden (CNVsHigh) was associated with worse clinicopathological characteristics and poor prognosis. Furthermore, our study also revealed that conditioned media (CM) of CNVsHigh genetic profile ALM cell line was associated with pro-tumoral, pro-angiogenic, and immunosuppressive secretome profiles. In addition, CM of CNVsHigh cell lines in vitro promotes macrophage polarization to immunosuppressive phenotype. Moreover, we observed an increased presence of immunosuppressive tumor-associated macrophages (TAMs) at the invasive front (IF) of CNVsHigh ALM biopsies. This research reveals the adverse prognostic impact of CNVsHigh in ALM patients, establishing a novel link with a pro-tumor secretome, offering potential biomarkers for prognosis and personalized treatment to enhanced disease monitoring in ALM patients.

The pharmacotherapeutic management of nail unit and acral melanomas

INTRODUCTION

Acral and nail unit melanomas are rare subtypes of melanoma, which have poor prognoses. Current guidelines for optimal treatment are lacking. Recent clinical trials have evaluated new pharmacotherapeutic agents for melanoma treatment, with dramatically improved survival rates; however, studies on acral and nail unit melanomas are limited in comparison to trials on cutaneous melanoma.

AREAS COVERED

This is a comprehensive review of the literature regarding the available treatment options for acral and nail unit melanomas, with consideration of safety and tolerability.

EXPERT OPINION

Programmed cell death protein 1 inhibitors are more efficacious than cytotoxic T lymphocyte-associated antigen-4 blockers in acral and nail unit melanomas, although both are well-tolerated. Tyrosine kinase inhibitors have good clinical activity, however, data on safety is relatively limited. There is minimal data on high dose interferon α-2b and cyclin-dependent kinase 4 and 6 inhibitors, and efficacy and safety must be evaluated in future trials before they can be recommended for use in this patient population. Prospective clinical trials on acral and nail unit melanomas are lacking, and must be performed in large patient populations, with international collaboration likely necessary in order to enroll adequate participants.

Nanotechnology Addressing Cutaneous Melanoma: The Italian Landscape

Cutaneous melanoma is one of the most aggressive solid tumors, with a low survival for the metastatic stage. Currently, clinical melanoma treatments include surgery, chemotherapy, targeted therapy, immunotherapy and radiotherapy. Of note, innovative therapeutic regimens concern the administration of multitarget drugs in tandem, in order to improve therapeutic efficacy. However, also, if this drug combination is clinically relevant, the patient's response is not yet optimal. In this scenario, nanotechnology-based delivery systems can play a crucial role in the clinical treatment of advanced melanoma. In fact, their nano-features enable targeted drug delivery at a cellular level by overcoming biological barriers. Various nanomedicines have been proposed for the treatment of cutaneous melanoma, and a relevant number of them are undergoing clinical trials. In Italy, researchers are focusing on the pharmaceutical development of nanoformulations for malignant melanoma therapy. The present review reports an overview of the main melanoma-addressed nanomedicines currently under study in Italy, alongside the state of the art of melanoma therapy. Moreover, the latest Italian advances concerning the pre-clinical evaluation of nanomedicines for melanoma are described.

Pathology of Melanoma

Melanoma is an aggressive malignancy arising from melanocytes in the skin and rarely in extracutaneous sites. The understanding of pathology of melanoma has evolved over the years, with the initial classifications based on the clinical and microscopic features to the current use of immunohistochemistry and genetic sequencing. The depth of invasion and lymph node metastasis are still the most important prognostic features of melanoma. Other important prognostic features include ulceration, lymphovascular invasion, mitosis, and tumor-infiltrating lymphocytes. This article reviews the pathology of melanoma and its precursor lesions, along with the recent advances in pathologic diagnosis of melanoma.

TERT copy gain predicts the outcome of high-dose interferon α-2b therapy in acral melanoma

Background

Asian populations are more likely to develop acral melanoma (AM) than Caucasians. The high-dose interferon (HD-IFN) α-2b regimen is the main adjuvant treatment for AM. TERT encodes the catalytic subunit of telomerase reverse transcriptase, which plays an important role in melanoma. Frequent TERT mutation and increased TERT gene expression have been described in AM. Our study aimed to investigate the status and the clinical significance of TERT copy number in a large cohort of patients with AM and to analyze the relationship between TERT copy number gain and the efficiency of HD-IFN.

Patients and methods

A total of 573 melanoma samples were retrospectively collected and analyzed for TERT copy number via Sanger sequencing. Clinical data of patients were also collected.

Results

TERT copy gain (copy number >2) was detected in 257 of the 573 patients with AM (44.9%). Of the 573 patients, 81 (14.1%) had a high copy gain (copy number >4). Patients with ulceration showed a significantly higher copy gain rate of TERT compared to the patients without ulceration (P=0.028). Patients with a tumor thicker than 4 mm also had a higher copy number rate of TERT than those with <4 mm (P=0.048). Our results showed that the overall survival (OS) was not significantly different between patients with and without TERT copy gain (P=0.890). However, among the 278 patients who received an HD-IFN regimen, Kaplan–Meier survival analysis demonstrated a significant correlation between TERT copy gain and relapse-free survival (RFS) (P=0.008). In addition, multivariate Cox regression assays validated TERT copy gain to be an independent prognostic factor of RFS for patients with AM undergoing HD-IFN therapy (hazard ratio =1.50; P=0.019).

Conclusion

The copy number status of TERT might be a predictor for HD-IFN efficacy, but it is not a prognostic factor of OS in patients with AM.

High G2 and S-phase expressed 1 expression promotes acral melanoma progression and correlates with poor clinical prognosis

G2 and S‐phase expressed 1 (GTSE1) regulates cell cycle progression in human cancers. However, its significance and mechanism of action in acral melanoma (AM) remain unknown. In the present study, we found that GTSE1 expression was upregulated in advanced stage/metastatic AM tissues and metastatic cell lines, and correlated with higher stage (P = .028) and poor disease‐free survival (DFS) in patients with AM (P = .003). Cox regression assays validated GTSE1 expression to be an independent prognostic factor of DFS for patients with AM (P = .004). Ectopic expression of GTSE1 enhanced primary AM cell proliferation, invasion, and migration. Loss‐of‐function in GTSE1 attenuated metastatic AM cell proliferation and metastatic ability in vitro and in vivo. We additionally observed that inhibition of migration and invasion occurred concomitantly with a GTSE1 knockdown‐mediated increase in E‐cadherin and decreases in N‐cadherin and Slug. We further showed that integrin subunit alpha 2 (ITGA2) interacts with GTSE1 and is a downstream effector of GTSE1. Further, ITGA2 levels were positively correlated with GTSE1 expression in human AM tissues. Ectopic ITGA2 expression rescued siGTSE1‐mediated inhibition of migration and invasion, thereby restoring epithelial‐to‐mesenchymal transition (EMT). In conclusion, GTSE1 expression promotes AM progression and correlates with clinical outcomes of patients with AM, and may represent a promising therapeutic target to suppress AM progression.