Supplementary Figure S2 shows another example of an RS case with CARD9 expression. In 7 of the 15 RS samples, we were able to study the clonal relationship between the RS and the underlying CLL, while 6 cases were shown to be clonally related RS. The one RS case that was not clonally related to the underlying CLL was among the CARD9-negative cases (Supplementary Table S2). In five of the tested RS samples, we additionally analyzed the corresponding CLL specimen for CARD9 expression. This evidence concerns the gene CARD9 and B-cell chronic lymphocytic leukemia.