CCND1 locus and expression of cyclin D1 mRNA isoforms in MCL. (A) Schematic representation of the CCND1 locus and alternatively spliced cyclin D1 mRNA transcripts cyclin D1a and D1b. Shaded boxes represent coding sequences, open boxes represent noncoding exon sequences, and filled boxes on the dotted line indicate the location of qPCR probes. (B) The relative amount of cyclin D1 mRNA containing full-length 3′UTR in relation to all cyclin D1 mRNA transcripts measured by the exon 1-2 probe is shown on a log2 scale. The dotted line indicates the cutoff, below which more than 50% of transcripts lack full-length 3′UTR. Quartiles of proliferation as determined in a prior study¹⁹  are given on the x-axis with tumors in quartile 1 having the lowest and those in quartile 4 having the highest proliferation (P < .001 for any difference between quartiles). Number of samples analyzed were for Q1 n = 22, Q2 n = 20, Q3 n = 22, Q4 n = 20. (C) The A870G polymorphism at the last nucleotide of exon 4 (codon 241) was determined using an NciI RFLP. PCR primers are indicated by arrows, the NciI restriction site is underlined, and a representative analysis of cDNA samples separated on a 3% agarose gel with a size marker (m) in the first lane is shown. (D) The frequency of cyclin D1 G870 alleles (white columns) or A870 alleles (black columns) involved in the t(11;14) translocation is summarized for all patients as well as for each proliferation quartile. There was no significant difference in genotype of the translocated alleles between quartiles (P = .84). Number of samples analyzed were for Q1 n = 22, Q2 n = 23, Q3 n = 21, Q4 n = 22.