Messenger RNA expression of candidate genes of chromosome 4q in primary MM and MM cell lines relative to normal BM plasma cells (BMPCs) and PB mononuclear cells (PBMNCs). (A) Electrophoretic analysis of RT-PCR products shows representative transcript expression of CXCL1, CCNI, and PF4 in MM (cases 1 to 7), normal BMPCs (cases 1 to 4), normal PBMNCs (cases 1 to 2), and MM cell lines (RPMI-8226, LP-1, OPM-2, NCI-H929, and U-266). Nonexpression of CXCL1 is found in normal BMPCs, primary MM, and MM cell lines, and expression of CCNI is observed in all MM and normal samples. Conversely, down-regulation of MM primary samples and negligible expression of PF4 in MM cell lines are observed when compared with expressions in normal BMPCs and PBMNCs. GAPDH expression is displayed for normalization and mRNA quality control. (B) Quantitative RT-PCR shows down-regulation of PF4 in MM and MM cell lines (RPMI-8226, LP-1, OPM-2, NCI-H929, and U-266) relative to normal BMPCs and PBMNCs. The mean and range of fold changes are as follows: MM cell lines, not detected; MM, 0.41, 0 to 1.51; normal BMPCs, 1.08, 0.80 to 1.26; and normal PBMNCs, 1.15, 0.78 to 1.79. Expression level of less than 0.5 (dotted line) is classified as down-regulation. Gene expression is normalized by transcript expression of ACTB. Error bars represent SD.