Cyclin D1 RT-PCR in cell lines and cells. (A) MCL cell lines NCEB-1 and Granta and MM cell line U266 expressed cyclin D1 mRNA. Breast cancer cell lines MCF7 and MDA-MB-231 (231) were also cyclin D1⁺. K562 stem cell/erythroleukemia cells expressed low levels of cyclin D1. HL60 and Manca cells did not express cyclin D1 mRNA. SCLC cell line H82 was also cyclin D1^–. (B) Normal human B cells CD19⁺ (NB), EBV-immortalized human B cells (LCL1, LCL2), normal human T-cell clone (D160), and normal human T cells CD4⁺ (NT) were all cyclin D1^–. Pt1 indicates a sample of purified B cells from peripheral blood from a patient with t(11;14) B-cell malignancy and expressed cyclin D1 mRNA. Actin was used as control.