T(4;14) MM cell lines were treated with MMSET shRNAs for 3 days. (A) Whole cell lysates were prepared from infected cells and protein levels were analyzed by Western-blot. b-actin was used as an internal control. KMS12BM is a non-t(4;14) MM cell line, others are t(4;14) MM cell lines. (B) Determination of SLAMF7 expression in MM cell lines by indirect flow cytometric analysis. Ab control, isotype mouse IgG. ShLuc, control shRNA; Sh#4 and Sh#5, MMSET shRNAs. KMS11, KMS18, KMS28BM, NCI-H929 and OPM-2 are t(4;14) positive, other cell lines are t(4;14) negative. Results indicated SLAMF7 was universally over-expressed in t(4;14) MM cell lines and down-regulated by MMSET knockdown treatments. (C) Determination of SLAMF7 expression in primary MM cells by direct flow cytometric analysis. Ab control, mouse IgG2b-FITC. Patient samples N089, N104 and N140 are t(4;14) positive, and patient samples N048, N051 and N084 are t(4;14) negative.