The PTEN del-TECT (4 Color) FISH probe greatly increases the reliability of deletion detection, significantly decreasing the number of falsepositive events2 caused by cell truncation, an artifact of FFPE tissue processing. The PTEN Test probe is labeled in Orange and detects deletions of the PTEN gene. Probe A (WAPAL/BMPR1A) is located centromeric to the test probe and is labeled in green. Probe B (FAS) is located telomeric to the test probe and is labeled in aqua. The combination of the three colored probes (green, orange and aqua) in close proximity assists not only in eliminating the possibility of truncation of this region, but also in determining the actual size of the deletion. The centromere 10 probe labeled in red is included to help determine if chromosome 10 monosomies or polysomies are present.