PTEN microdeletions in xenotransplants of a T-ALL primary patient sample and in human thymocytes from healthy individuals. (A) Schematic representation of the xenotransplantation strategy. Several months posttransplant of patient no. 24’s leukemic cells into immunodeficient NSG mice (n = 9), cells from bone marrow, thymus, spleen, and liver were collected. Primary (×1) and secondary (×2) xenotransplanted material was then analyzed for the presence of any of the 3 different PTEN microdeletions. (B) Breakpoint sequences of PTEN microdeletions as detected in samples from primary (×1) and secondary (×2) xenotransplanted mice. Canonic CAC trinucleotide sequences or the corresponding GTG nucleotides in heptamer sequences are indicated in bold and underlined. (C) Sequences of the breakpoints for PTEN type I microdeletions as identified in thymocytes of healthy individuals (H-Thy1 – H-Thy3). BM, bone marrow; Spl, spleen; Thy, thymus.