Pre-miRNA profile of PEL. (A) Unsupervised cluster analysis of standardized dCT_U6 for pre-miRNAs using a correlation metric. Standardization was achieved by calculating Z scores across each individual array of dCT_U6. This technique eliminates variation in assay performance between individual samples. Red indicates higher abundance; blue, lower than median abundance; white, the median. (B,C) Enlarged view. (B) Cluster of pre-miRNAs with decreased abundance in PEL vis-à-vis tonsil. (C) Cluster of pre-miRNAs with increased abundance in PEL vis-à-vis tonsil. (D) Cluster of pre-miRNAs equal abundance in PEL vis-à-vis tonsil. (E) Cluster of pre-miRNAs with high abundance in PEL as well as in nonvirus-associated lymphoma lines. The cluster of absent pre-miRNAs is not shown separately.