TERT expression and telomerase activity of B-cell malignancies with and without aberration in the TERT-CLPTM1L locus. (A) Relative TERT mRNA expression determined by qRT-PCR. Cases 1, 3, 5, and 6 with 5p15.33 break by FISH were compared with CLL 1-11 showing no 5p15.33 aberration by FISH. The P value was estimated using the Mann-Whitney test. Samples with undetectable TERT mRNA expression were excluded from statistical analysis. (B) Telomerase activity measured by TRAP assay. Cases 1, 4, and 6 and cases 8 and 9 with 5p15.33 aberration by FISH were compared with CLL cases 1, 3, 4, 6, 10 and 11 and MCL cases 4 and 5 without aberration in this region by FISH. The relevant cytogenetic aberrations and the tumor cell contents are given in brackets.