| Popis |
Diagnosing ovarian sex cord-stromal tumors can be difficult in some cases due to the overlapping morphologic and immunohistochemical (IHC) features, especially for adult granulosa cell tumors (AGCTs), juvenile granulosa cell tumors (JGCTs), Sertoli-Leydig cell tumors (SLCTs), and thecomas. In such situations, molecular testing can be helpful, as these tumors are often associated with specific genetic alterations. SLCTs, for instance, are known to be associated with DICER1 mutations. However, expression of DICER1 has not yet been systematically investigated in sex cord-stromal tumors. We evaluated the potential use of DICER1 IHC for detecting DICER1 mutations in ovarian sex cord-stromal tumors, including 267 AGCTs, 38 SLCTs, 5 JGCTs, and 21 Leydig cell tumors/steroid cell tumors (SCTs). Specifically, DICER1 positivity was found in 21 of 38 (55.3%) of SLCTs and 16 of 21 (76.2%) of SCTs. All DICER1-positive moderately differentiated SLCTs harbored a DICER1 mutation. One DICER1-negative moderately differentiated SLCT carried 2 DICER1 mutations. Additionally, 3 of 10 well-differentiated SLCTs showed IHC positivity. No SCT harbored a DICER1 mutation. Among AGCTs, 4 of 267 (1.5%) were DICER1 positive, and 1 of these cases harbored 2 DICER1 mutations. No JGCT demonstrated a DICER1 mutation or expression. In cases with both analyses available, DICER1 expression was found in 39 of 273 (14.3%), whereas 21 of 273 (7.7%) harbored a DICER1 mutation. Using an optimal cutoff of >= 10% positive tumor cells, IHC closely matched mutational status (sensitivity of 90.5%, specificity of 92.1%). Our study found substantial concordance between DICER1 IHC and mutation status in a subset of sex cord-stromal tumors, suggesting that IHC detection of DICER1 protein may serve as a useful surrogate marker for DICER1 mutation, especially in SLCTs and AGCTs. This could be particularly valuable in settings where molecular testing is limited by cost and/or availability. However, in SCTs, the DICER1 expression is common but unrelated to DICER1 mutation. This suggests that alternative mechanisms, potentially involving androgen-related pathways, may contribute to DICER1 expression in these tumors. (c) 2026 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
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