 primitive neuroectodermal tumor, neuroblastoma, and others. However to date, the absence of SMARCA4 protein is highly sensitive and specific for SCCOHT and can be used to distinguish it from other ovarian tumors with similar histology to facilitate diagnosis.

SCCOHTs are extremely aggressive and refractory to treatment that most commonly includes surgical debulking followed by high-dose chemotherapy and/or radiation.[@cit0005] Some evidence suggests that chemotherapeutic combinations including cisplatin or carboplatin, etoposide and vinca alkaloids may be associated with improved survival, yet patient outcomes are abysmal in most cases with a 65% recurrence rate and 2-year survival less than 35%.[@cit0005] SCCOHT rarity limits the implementation of prospective clinical trials to guide effective treatment and its infrequency has also limited the study of its pathogenesis to uncover potential therapeutic vulnerabilities. Our finding that the majority of SCCOHTs contain SMARCA4 mutations amidst otherwise simple genomic backgrounds provides an opportunity to empirically develop effective treatment strategies with a high probability of impact for many of these patients. Given that this disease derives in virtually all cases from the loss of a tumor suppressor, the path to an effective small molecule may hinge on identification of a synthetic lethal target. To this end, a synthetic lethal dependence of SMARCA4-deficient cancers cells on SMARCA2 has recently been described in non-small cell lung cancer, ovarian and liver cancer cell lines.[@cit0032] This dependence is likely due to SMARCA2\'s status as the only known alternative ATPase subunit of the SWI/SNF complex. However, preliminary SMARCA2 staining in 2 SCCOHT cell lines showed lack of protein in both cases (data not shown), suggesting that SCCOHT may lack the expression of both SMARCA2 and SMARCA4 and that investigation of other synthetic lethal partners is therefore warranted. Although it has been shown in other cancers such as non-small cell lung adenocarcino