{Reference Type}: Case Reports
{Title}: Marked Response to Nivolumab by a Patient With SMARCA4-Deficient Undifferentiated Urothelial Carcinoma Showing High PD-L1 Expression: A Case Report.
{Author}: Arihara Y;Omori G;Kobayashi K;Sugita S;Murase K;Kubo T;Idogawa M;Hasegawa T;Takada K;
{Journal}: Cancer Rep (Hoboken)
{Volume}: 7
{Issue}: 6
{Year}: 2024 Jun
暂无{DOI}: 10.1002/cnr2.2127
{Abstract}: <B>BACKGROUND: </B>SMARCA4 is a component gene of the SWI/SNF (SWItch/Sucrose NonFermentable) chromatin remodeling complex; undifferentiated tumors associated with its functional deletion have been described in several organs. However, no established treatment for these tumors currently exists.<BR><B>METHODS: </B>In this study, we report a case of a SMARCA4-deficient undifferentiated urothelial carcinoma with high PD-L1 expression that was effectively treated with nivolumab after early relapse following treatment for non-invasive bladder cancer. The histological morphology of the rhabdoid-like undifferentiated tumor of unknown primary led us to suspect a SWI/SNF-deficient tumor, and subsequent immunostaining led to the diagnosis of a SMARCA4-deficient undifferentiated tumor. This effort also led to the identification of the developmental origin of this SMARCA4-deficient undifferentiated tumor as a non-invasive bladder cancer. We also carried out a detailed immune phenotypic assay on peripheral T cells. In brief, a phenotypic change of CD8+T cells from naive to terminally differentiated effector memory cells was observed.<BR><B>CONCLUSIONS: </B>Regardless of the organ of cancer origin or cancer type, SWI/SNF-deficient tumors should be suspected in undifferentiated and dedifferentiated tumors, and immune checkpoint inhibitors may be considered as a promising treatment option for this type of tumor. The pathogenesis of SMARCA4-deficient anaplastic tumors awaits further elucidation for therapeutic development.