ALK is frequently phosphorylated in Merkel cell carcinoma and associates with longer survival

Prognostic significance of ALK high expression in SCLC: a 9-year cohort analysis

Purpose

The aim of this study was to investigate the prognostic value of the abnormal expression of anaplastic lymphoma kinase (ALK) protein in patients with small cell lung cancer (SCLC) based on 9-year data from our center.

Methods

A retrospective cohort study was conducted to assess the clinical outcomes of patients with ALK-positive SCLC diagnosed in our hospital over the past 9 years. We used public databases to analyze the expression of ALK in pan-cancer and its prognostic value and analyzed the correlation between ALK and SCLC prognosis-related genes.

Results

A total of 685 patients diagnosed with SCLC underwent ALK testing, and 59 patients were identified to have abnormal expression of the ALK protein, with 10 cases showing strong expression, 14 cases displaying moderate expression, and 35 cases exhibiting weak expression. The median age of the ALK-positive cohort was 64 years (range: 58-70 years), 91.5% (54/59) were male, 61.0% (36/59) were smokers, and the median overall survival (mOS) was 7.0 months (95% CI: 4.5-9.5 months). Within this cohort, the mOS for the ALK (+) subgroup was 4.0 months (95% CI: 2.9-5.1 months), the mOS for the ALK (++) subgroup was 10.0 months (95% CI: 4.9-15.1 months), and the mOS for the ALK (+++) subgroup was 12.0 months (95% CI: 7.4-16.6 months). Kaplan-Meier revealed that the mOS of the ALKLow group was significantly worse than that of the ALKHigh group [mOS: 4.0 months (95% CI: 2.9-5.1 months) versus 11.0 months (95% CI: 8.3-13.7 months), p = 0.009]. Following covariate adjustment using a Cox regression model, it was indicated that the level of abnormal expression of the ALK protein was an independent prognostic factor for patients with SCLC (HR: 0.486, 95% CI: 0.271-0.871, p = 0.015).

Conclusion

The prognosis for patients with SCLC with strong abnormal expression of the ALK protein was significantly better than those with weak expression.

NSD3::FGFR1: A Novel Gene Fusion First to Be Described in Merkel Cell Carcinoma

ABSTRACT

Merkel cell carcinomas (MCCs) exhibit diverse molecular profiles, often categorized by their association with Merkel cell polyoma virus (MCPyV). MCPyV-associated MCCs typically display a low tumor mutational burden (TMB), lacking both somatic mutations and ultraviolet signature. By contrast, MCPyV-negative MCCs commonly arise in sun-exposed skin and frequently exhibit a high TMB, along with TERT promoter mutation (TPM) and somatic mutations, particularly in TP53 and RB1. Gene fusions are exceedingly rare in MCCs, and their specific frequency and fusion transcripts remain largely unexplored. Here, we present a unique case of MCPyV-associated MCC characterized by NSD3::FGFR1 fusion, representing a novel fusion transcript not previously reported in MCCs. A 72-year-old White man presented with a cyst-like nodule on the left elbow, which had progressively increased in size over a span of 6 months. Excisional biopsy specimen revealed a neuroendocrine carcinoma diffusely expressing CK20 (perinuclear dot-like), synaptophysin, CD56, NSE, and MCPyV, consistent with MCC. Next-generation sequencing identified a NSD3::FGFR1 fusion without any additional somatic mutations, including TP53 and RB1 mutations, or TPM. Although NSD3::FGFR1 fusion has been sporadically reported in other solid tumors, such as pulmonary squamous cell carcinoma, its identification in an MCC is unprecedented to our knowledge. This novel finding not only underscores the uniqueness of our case but also contributes to the evolving understanding of the molecular landscape of MCCs, particularly MCPyV-associated MCCs.

Advancing Treatment Options for Merkel Cell Carcinoma: A Review of Tumor-Targeted Therapies

Although rare, Merkel cell carcinoma (MCC) is a highly aggressive and increasingly prevalent neuroendocrine cancer of the skin. While current interventions, including surgical resection, radiation, and immunotherapy have been employed in treating many patients, those who remain unresponsive to treatment are met with sparse alternatives and a grim prognosis. For this reason, it is of interest to expand the repertoire of available therapies for MCC patients who remain resistant to current primary interventions. Recently, our improved mechanistic understanding of aberrant cell signaling observed in both MCPyV-positive and -negative MCC has facilitated exploration into several small molecules and inhibitors, among them receptor tyrosine kinase inhibitors (TKIs) and somatostatin analogs (SSAs), both of which have positively improved response rates and reduced tumor volumes upon application to treatment of MCC. The introduction of such targeted therapies into treatment protocols holds promise for more personalized care tailored towards patients of diverse subtypes, thereby improving outcomes and mitigating tumor burden, especially for treatment-resistant individuals. In this review, we characterize recent findings surrounding targeted treatments that have been applied to MCC and provide an overview of emerging perspectives on translatable options that can be further developed to offer additional therapeutic avenues for patients with the disease.

Somatostatin receptor expression in Merkel cell carcinoma: correlation with clinical data

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, high-grade neuroendocrine neoplasm (NEN) of the skin. Somatostatin receptors (SSTRs) are G protein-linked receptors that regulate cell proliferation and growth. SSTRs are expressed in many NENs; however, scant information is available on their expression in MCCs or their association with clinical parameters and patient outcomes.

MATERIAL AND METHODS

This retrospective study was conducted at Helsinki University Hospital and the University of Helsinki. Using a tissue microarray, we investigated SSTR1-5 expression by immunohistochemistry in 99 MCC tissue samples. Samples were collected between 1983 and 2017 and coupled with the patients' clinical data.

RESULTS

SSTR2-SSTR5 were detected in 69%, 6%, 4%, and 1% of the tumours, respectively. However, SSTR1 expression was not observed. Cytoplasmic SSTR2 positivity was associated with metastatic disease at the time of diagnosis (p = 0.009), but it did not correlate with disease-specificity or overall survival.

CONCLUSION

SSTR2-5 expression was observed in MCCs. In particular, SSTR2 expression is clinically valid because it is associated with metastatic disease at the time of diagnosis and can thus serve as a prognostic marker. Moreover, SSTR2 overexpression provides a molecular basis for tumour imaging and treatment with somatostatin analogues.

Clinical-Pathological Evaluation and Prognostic Analysis of 228 Merkel Cell Carcinomas Focusing on Tumor-Infiltrating Lymphocytes, MCPYV Infection and ALK Expression

Merkel cell carcinoma is a rare and aggressive primary neuroendocrine carcinoma of the skin, whose pathogenesis can be traced back to UV radiation damage or Merkel cell polyomavirus (MCPyV) infection. Despite some improvements on the characterization of the disease partly due to its increased incidence, crucial pathogenetic and prognostic factors still need to be refined. A consecutive series of 228 MCC from three hospitals in Turin was collected with the aim of both analyzing the apparent increase in MCC incidence in our area and investigating the distribution and prognostic role of clinical-pathological parameters, with a focus on MCPyV status, ALK tumor expression and tumor infiltrating lymphocytes (TILs). Review of morphology and conventional immunohistochemical staining was possible in 191 cases. In 50 cases, the expression of the novel neuroendocrine marker INSM1 was additionally assessed. Fourteen cases of MCC of unknown primary skin lesion were identified and separately analyzed. While confirming an exponential trend in MCC incidence in the last decades and providing a description of histological and cytological features of a large series of MCC, the present study concludes that 1) INSM1 is a highly sensitive marker in both skin and lymph node primary MCC; 2) positive MCPyV status, brisk TILs and lower tumor size and thickness are independent positive prognostic parameters, and the combination of the former two may provide a novel tool for prognostic stratification; 3) ALK is expressed 87% of MCC and associated with positive viral status, and could represent a prognostic biomarker, if validated in larger series.