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Soo Park, MD
Soo Park, MD
Posted: Thursday, February 1, 2024
Potential heritable risk factors for Merkel cell carcinoma have been identified for what study authors believe may be the first time. Isaac Brownell, MD, PhD, of the National Institutes of Health, Bethesda, Maryland, and colleagues discovered that variants in cancer predisposition syndrome genes were found in 19% of patients with early-onset Merkel cell carcinoma (ie, diagnosed at younger than age 50). They think genetic counseling and testing should be considered for these younger patients who present with this aggressive skin cancer.
“Merkel cell carcinoma has not [previously] been considered to run in families,” wrote the researchers in JAMA Dermatology. Additionally, it has not “been associated with well-studied syndromes such as hereditary breast and ovarian cancer [syndrome].”
The team described the outcomes of their case-control study of 1,012 individuals: 37 with early-onset Merkel cell carcinoma, 45 with later-onset Merkel cell carcinoma, and 930 unrelated controls without the disease. Of all patients who develop this malignancy annually, about 4% are younger than age 50. The participants with Merkel cell carcinoma in this study were all treated at the University of Washington in Seattle between 2003 and 2019. Of 1,637 participants, 78 (5%) presented when younger than age 50; of them, 37 had peripheral blood mononuclear cells available for genome sequencing.
Of the 37 patients, 7 (19%) stood out: 6 patients had germline variants associated with hereditary cancer syndromes, including for breast, ovarian, and other cancers (ATM = 2, BRCA1 = 2, BRCA2 = 1, TP53 = 1), and 1 patient had a variant of MAGT1 associated with immunodeficiency and lymphoma. The early-onset Merkel cell carcinoma cohort was significantly (P < .001) enriched for cancer-predisposing pathogenic or likely pathogenic variants; the variants were not identified in any patients with later-onset Merkel cell carcinoma, and they were identified in nine controls (1%).
Disclosure: For full disclosure of the study authors, visit jamanetwork.com.
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