Background: As the molecular mechanisms in melanoma chemoresistance remain unknown to date, we hypothesized these tumors to express the ATP-binding cassette (ABC) transporter G2 (ABCG2/MXR/BCRP1/ABCP1), a recently detected membrane transporter and putative stem-cell marker. Besides melanoma, we addressed the neuroendocrine carcinoma of the skin (Merkel cell carcinoma), another cutaneous cancer supposed to originate from neuroectoderm and usually chemoresistant.
Methods And Results: Upon semiquantitative reverse transcription polymerase chain reaction, ABCG2 mRNA expression was not upregulated in 18 melanoma resection specimens when compared with 19 acquired melanocytic nevi from which melanomas are known to often arise (Mantel-Haenszel test, p=0.3). At protein level, immunohistochemistry was negative in all 66 investigated melanoma resection specimens (50 primary melanomas and 16 cutaneous/subcutaneous metastases) and in 19 acquired melanocytic nevi. Among 29 neuroendocrine carcinomas of the skin, ABCG2 protein was detected in single clusters of cells in three tumors. As a positive control, three dermatofibrosarcomas were also stained and showed ABCG2 protein expression of the endothelial cells of the blood vessels.
Conclusion: Altogether, chemoresistance of melanomas and neuroendocrine carcinomas of the skin cannot be explained by expression of the ABCG2-chemoresistance gene. Most of these tumors do not exhibit this potential stem-cell feature.
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http://dx.doi.org/10.1111/j.0303-6987.2005.00359.x | DOI Listing |
Am J Clin Pathol
January 2025
Department of Pathology, Duke University Medical Center, Durham, NC, US.
Objective: Distinguishing grade 3 pancreatic neuroendocrine tumors (PanNETs) from neuroendocrine carcinomas (PanNECs) is sometimes challenging. Recently, a diffuse p16-positive pattern was reported in PanNECs but not in grade 3 PanNETs, suggesting that p16 could help differentiate these entities. This study aimed to investigate p16 expression in PanNETs of various grades and its association with clinicopathologic features.
View Article and Find Full Text PDFCancer Rep (Hoboken)
January 2025
Department of Thoracic Surgery, Affiliated Hospital of Zunyi Medical College, Zunyi, People's Republic of China.
Background: Neuroendocrine tumors of the thymus (NETT) are rare and malignant tumors that arise in the anterior mediastinum. These tumors can exhibit aggressive behavior and may involve surrounding critical structures, such as the superior vena cava. This case contributes to the literature by presenting a recurrent thymic carcinoma with invasion of major blood vessels, including the superior vena cava, and the complexities involved in its surgical management.
View Article and Find Full Text PDFJ Neuroendocrinol
January 2025
Department of Gastrointestinal Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA.
Colonic neuroendocrine tumors (NETs), excluding rectal NETs, are often described as relatively common and aggressive, with inferior median survival compared with other gastrointestinal (GI) primary sites. However, epidemiological databases may conflate well-differentiated NETs with poorly differentiated neuroendocrine carcinomas (NECs), leading to a lack of precise data on the prevalence, clinical behavior, and prognosis of well-differentiated colonic NETs. We analyzed a large institutional database to identify patients with well-differentiated NETs originating in the colon, excluding rectal NETs.
View Article and Find Full Text PDFPeerJ
January 2025
Instituto de Patologia e Imunologia Molecular da Universidade do Porto (IPATIMUP), i3S-Institute for Research & Innovation in Health, Porto, Portugal.
Background: The differential diagnosis between benign and malignant thyroid nodules continues to be a major challenge in clinical practice. The rising incidence of thyroid neoplasm and the low incidence of aggressive thyroid carcinoma, urges the exploration of strategies to improve the diagnostic accuracy in a pre-surgical phase, particularly for indeterminate nodules, and to prevent unnecessary surgeries. Only in 2022, the 5th WHO Classification of Endocrine and Neuroendocrine Tumors, and in 2023, the 3rd Bethesda System for Reporting Thyroid Cytopathology and the European Thyroid Association included biomarkers in their guidelines.
View Article and Find Full Text PDFDiscov Oncol
January 2025
Division of Hematology Oncology, Penn State College of Medicine, 500 University Dr, Hershey, PA, 17033, USA.
Background: The role of adjuvant chemotherapy in early-stage small cell lung cancer (SCLC) and large cell neuroendocrine carcinoma (LCNEC) remains unclear, particularly for small tumors. This study assesses the survival benefits of adjuvant chemotherapy after surgical resection with a novel focus on tumors less than 1 cm.
Materials And Methods: Data from the National Cancer Database (NCDB) was extracted for patients with SCLC (n = 11,962) and LCNEC (n = 6821) who underwent surgical resection between 2004 and 2020.
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