In the KarMMa study, loss of BCMA on tumor cells was observed in 3/71 (4%) of the patients at progression by immunohistochemistry, while the vast majority suffered BCMA-positive relapse, suggesting BCMA antigen loss as an infrequent cause of escape from anti-BCMA CAR-T therapy (22). This evidence concerns the gene TNFRSF17 and neoplasm.