TRK Protein Expression in Merkel Cell Carcinoma Is Not Caused by Fusions.

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous malignant tumor with neuroendocrine differentiation, with a rapidly growing incidence rate, high risk of recurrence, and aggressive behavior. The available therapeutic options for advanced disease are limited and there is a pressing need for new treatments. Tumors harboring fusions involving one of the neurotrophin receptor tyrosine kinase () genes are now actionable with targeted inhibitors.

The Molecular Landscape of Primary Acral Melanoma: A Multicenter Study of the Italian Melanoma Intergroup (IMI).

Acral melanoma (AM) is a rare and aggressive subtype of melanoma affecting the palms, soles, and nail apparatus with similar incidence among different ethnicities. AM is unrelated to ultraviolet radiation and has a low mutation burden but frequent chromosomal rearrangements and gene amplifications. Next generation sequencing of 33 genes and somatic copy number variation (CNV) analysis with genome-wide single nucleotide polymorphism arrays were performed in order to molecularly characterize 48 primary AMs of Italian patients in association with clinicopathological and prognostic features.

TERT Promoter Mutations Differently Correlate with the Clinical Outcome of MAPK Inhibitor-Treated Melanoma Patients.

Resistance is a major challenge in the management of mitogen-activated protein kinase inhibitor (MAPKi)-treated metastatic melanoma. Tumor genetic alterations can cause MAPK pathway reactivation, leading to lack of response and poor outcome. Characterization of the mutational profile in patients with melanoma might be crucial for patient-tailored treatment choices.

Periostin and Epithelial-Mesenchymal Transition Score as Novel Prognostic Markers for Leiomyosarcoma, Myxofibrosarcoma, and Undifferentiated Pleomorphic Sarcoma.

Purpose: Interpatient clinical variability in soft-tissue sarcomas (STS) highlights the need for novel prognostic markers supporting patient risk stratification. As sarcomas might exhibit a more mesenchymal or a more epithelial state, we focused on epithelial-mesenchymal and mesenchymal-epithelial transitions (EMT/MET) for prognostic clues, and selected three histotypes with variable aggressiveness.

Experimental Design: The expression of EMT/MET-related factors was measured by qRT-PCR in 55 tumor samples from patients with leiomyosarcoma, myxofibrosarcoma, or undifferentiated pleomorphic sarcoma.

Prevalence of ALK gene alterations among the spectrum of plexiform spitzoid lesions.

Background: ALK receptor tyrosine kinase gene (ALK) rearrangements have been described in spitzoid lesions with a plexiform growth pattern.

Objective: To investigate the prevalence of ALK alterations in a large series of spitzoid lesions.

Methods: ALK immunohistochemical and fluorescence in situ hybridization analyses of 78 spitzoid plexiform lesions including 41 Spitz nevi, 29 atypical Spitz tumors (ASTs), and 8 spitzoid melanomas.

Gene Copy Number and Mutant Allele Frequency Correlate with Time to Progression in Metastatic Melanoma Patients Treated with MAPK Inhibitors.

Metastatic melanoma is characterized by complex genomic alterations, including a high rate of mutations in driver genes and widespread deletions and amplifications encompassing various chromosome regions. Among them, chromosome 7 is frequently gained in -mutant melanoma, inducing a mutant allele-specific imbalance. Although amplification is a known mechanism of acquired resistance to therapy with MAPK inhibitors, it is still unclear if copy-number variation and mutant allele imbalance at baseline can be associated with response to treatment.

Extraskeletal Myxoid Chondrosarcoma of the Foot Clinically Mimicking Plantar Fibromatosis.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma usually presenting in proximal extremities of middle-aged men. The authors discuss a unique case of EMC, localized in the plantar foot of a 76-year-old woman, clinically suspected as plantar fibromatosis. It is important to avoid misdiagnosis of EMC because of their propensity for late recurrence and their metastatic potential.