Study Finds Stem Cell Markers Point to Origin and Prognosis in Merkel Cell Carcinoma
Posted: Tuesday, August 24, 2021
Immunoexpression of LRIG1 appears to be correlated with a positive prognosis in patients with Merkel cell carcinoma. Observation of several stem cell markers, including the cell-surface protein leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), in this aggressive skin cancer appears to support the theory that the disease may arise from epithelial stem cells.
“The natural potential of these epithelial stem cells to differentiate into Merkel cells, their sensitivity to oncogenic stimuli such as UV radiation, and the fact that Merkel cell carcinoma exhibits expression of epithelial stem cell markers known to be expressed in another malignancy that originates from these cells advocate the possibility that they may serve as cells of origin in Merkel cell carcinoma as well,” according to Virve Koljonen, MD, of the University of Helsinki and colleagues, in Virchows Archiv, the official journal of the European Society of Pathology.
Data and tissue of 137 patients with Merkel cell carcinoma were provided by the Finnish Cancer Registry and Helsinki University Hospital files. In the cohort, the mean age at the time of diagnosis was 77, and 69% of patients were female. For 107 patients, Merkel cell polyomavirus (MCPyV) status was known, with 68% being positive. LRIG1 expression was observed in 86% of samples.
More LRIG1 expression seemed to be associated with a better overall survival rate (P = .037). “The 5-year overall survival rate was 15.8% for LRIG1-negative cases, 39.1% for cases showing weak LRIG1 expression, and 42.2% for cases showing intermediate or strong LRIG1 expression,” the study authors commented. In addition, MCPyV large T-antigen expression (P = .020) and younger age at diagnosis (P = .003) were both found to be associated with stronger LRIG1 expression.
The study’s authors noted that MCPyV status was “statistically more relevant,” and therefore perhaps a better prognostic marker for use in clinical settings. However, they noted, larger data sets are needed to definitively identify epithelial stem cells as the cause of certain Merkel cell tumors.
Disclosure: The study authors reported no conflicts of interest.
