Clinical utility of SMARCA4 testing by immunohistochemistry in rare ovarian tumours
Menée auprès d'une cohorte de 44 patientes atteintes d'un carcinome à petites cellules de l'ovaire de type hypercalcémiant (SCCOHT) et 94 patientes atteintes d'une néoplasie ovarienne rare fréquemment diagnostiquée à tort comme SCCOHT, cette étude évalue la sensibilité et la spécificité d'un test immuno-histochimique basé sur l'expression de l'hélicase SMARCA4 pour diagnostiquer la maladie
Background : Ovarian small cell carcinoma, hypercalcaemic type (SCCOHT) is a rare and lethal disease affecting young women. As histological diagnosis is challenging and urgent, there is a clear need for a robust diagnostic test. While mutations in the chromatin-remodelling gene, SMARCA4, appear to be typical, it may not be feasible routinely to be clinically relevant.
Methods : Previous studies have described the value of SMARCA4 IHC to differentiate SCCOHT from ovarian neoplasms (ON), with similar histologic appearances. We aimed to evaluate its clinical utility among a cohort of 44 SCCOHT and 94 rare ON frequently misdiagnosed as SCCOHT.
Results : Forty-three percent (16/36) of SCCOHT had been classified locally as non-SCCOHT confirming the diagnosis challenge. Sensitivity and specificity of SMARCA4 IHC were excellent at 88% and 94%, respectively. In a community setting with a much lower prevalence of the disease, estimated PPV is 40% while NPV remained high at 99%. Finally, among the 16 SCCOHT misclassified locally, SMARCA4 IHC testing would have resulted in corrected diagnosis in 88% of cases.
Conclusions : SMARCA4 IHC is a highly sensitive, and specific test for the diagnosis of SCCOHT and is of huge clinical utility in providing a timely and accurate diagnosis of this challenging disease.
British Journal of Cancer , résumé, 2019