Down-regulated expression of TCF8 in ATLL cells. (A) The expression profiles of the genes mapped within the deletion region at 10p11. Semiquantitative reverse-transcription PCR (RT-PCR) was performed to determine the expression of the genes mapped within the deletion region. TCF8, ARHGAP12, KIF5B, CCDC7, EPC1, C10orf68, ITGB1, and NRP1 showed a single band of amplified cDNA from CD4⁺ T lymphocytes from healthy volunteers as controls and from ATLL cells from the patients. A band of HTLV1 Tax was amplified from only 1 of 8 ATLL cells. A vertical line has been inserted to indicate a repositioned gel lane. (B) Quantitative RT-PCR analysis of TCF8 mRNA in 4 samples of CD4⁺ T lymphocytes from healthy volunteers and 8 samples of ATLL cells from the patients. The data were normalized to β-actin mRNA and calibrated to the TCF8/β-actin ratio (ΔCT) in the case of healthy volunteer no. 1, as a relative expression rate of 100. The data are the mean and standard deviation of 2^−ΔΔCt in a duplicate assay. Two patients (indicated by *) have the chromosome 10p11.2 abnormalities. (C) Quantitative RT-PCR analysis of TCF8 mRNA in various types of T lymphoblastic leukemia cell lines. MOLT4, MKB1, KAWAI, and Jurkat are T-lymphoid leukemia cell lines; MT2 and HUT102 are HTLV-1–infected cell lines; and ED, KOB, KK1, SO4, S1T, and Su9T are ATLL cell lines. Three ATLL cell lines (indicated by *) showed the deletion of chromosome 10p11.2 with TCF8.