MiRNAs are differentially expressed in tFL. (A) miRNAs were quantified in paired FL-tFL samples from 8 patients (analyzed by TaqMan Array Human MicroRNA Cards; supplemental Methods). Expression of each miRNA was centered on the median miRNA expression in all samples and visualized in a heatmap (MeV software). Lower expression is indicated in blue, and higher expression in yellow (linear scale). The differences in miRNA expression between FL vs tFL were tested by paired t test (P < .05; fold change ≥2). Patient characteristics are listed in supplemental Table 1 (FL patients 1-8). All tFLs were transformations (transf) to histologically verified DLBCL. All RNA samples in the analyses were isolated from FFPE tissue. (B) Validation of miR-150 levels in paired FL and tFL samples from 13 patients. The same 16 samples from panel A and additional 10 samples (5 pairs) were analyzed by individual quantitative reverse transcription polymerase chain reaction (qRT-PCR; tested by paired t test; patient characteristics listed in supplemental Table 1 [FL patients 1-13]). (C) miR-150 expression in patients who did not experience transformation during follow-up (FL non-transf) and those with FL before transformation (FL before transf; patient later transformed to DLBCL), tFL (at sampling), and primary DLBCL (tested by Mann-Whitney test). The median follow-up for patients in the nontransforming FL group was 131 months (range, 2-276 months), the median follow-up for those in the FL before transformation group was 95 months (range, 25-231 months), and the median follow-up for those in the tFL group was 98 months (range, 5-231 months). NS, not significant.