MXD1 and carcinoma: Both cases with novel NUTM1 fusion partners (BCORL1 and MXD1) didnot show NUT immunoreactivity in this series.14 This observation is shared by other authors who found that NUT protein wasinconsistently expressed by NUT-variant carcinomas, suggesting that variant fusion proteinsmay be expressed at lower levels than the BRD3 and BRD4 fusion products.15 Because NUT-variant carcinomas may not be susceptible to bromodomain inhibitor therapy,identifying the fusion partner may become necessary with respect to the prediction ofresponsiveness to bromodomain inhibitor therapy.13