Identification of PTEN microdeletions in T-ALL patients. (A) MLPA electropherograms of normal reference DNA and representative examples of T-ALL patients with heterozygous or homozygous PTEN microdeletions affecting exons 2-3 or a heterozygous deletion of exons 4-5. Fluorescence intensities of amplified PCR products for specific PTEN exons are shown. PCR product sizes are shown at the top. Each arrow points to a homo- or heterozygously deleted exon. (B) Array-CGH plot exhibiting the homozygous PTEN exon 2-3 microdeletion in one T-ALL patient sample.