Test Directory

• P53, 17p13
• ATM, 11q22.3

In chronic lymphocytic leukemia (CLL), the most frequent chromosomal aberrations are deletions of 13q, 11q, 17p, and trisomy 12. Occurring in 50%-60% of patients, del(13q) removes the DLEU2-mir-15-16 cluster, which regulates expression of anti-apoptotic and cell cycle regulatory proteins. del(11q), detected in 10-20% patients, removes ATM, and del(17p) (5-10% of patients) results in loss of TP53. Trisomy 12 occurs in 15-20% of patients, although the genes involved remain unknown. The most frequently mutated genes in CLL/small lymphocytic lymphoma (SLL) at the time of first treatment are NOTCH1 (10-15%), ATM (10-15%), SF3B1 (10%), TP53 (5-10%), and BIRC3 (5%). FISH for abnormalities of chromosome ATM/TP53 can be performed on interphase or metaphase cells.

Specimen Types: Leukemic Blood or Bone Marrow

Preferred Collection Container: Green Top (Sodium Heparin)

Alternate Collection Container: Lavendar Top (EDTA)

Desired Specimen Volume: 3 - 5 mL

Minimum Acceptable Volume: 1 mL

• Lithium heparin is not acceptable.
• Specimens must be collected in a sterile collection container.

Each specimen must be accompanied by a requisition form, script, electronic order or physician note. Each order must indicate the reason for testing (diagnosis).

• Transport to the laboratory at room temperature.
• Store specimen as whole blood, in original tube, at room temperature and deliver to lab within 24 hours.
• If specimen cannot be delivered within 24 hours, store in refrigerator. Do not freeze specimen.
• Specimens collected on the weekends must be refrigerated upon arrival at HNL Lab Medicine.

• Specimen frozen
• Specimen arriving without any form of patient identification (unlabeled)
• Specimen with attached needles
• Specimen arriving with broken or leaking collection tube
• Unfixed specimen treated with fixative

In a normal cell, the expected signal pattern is two red signals and two green signals. In an abnormal cell containing the deletion, the expected signal pattern is one red signal and two green signals for TP53 deletion and two red signals and one green signal for ATM deletion.

• FISH P53/ATM Combo
• Tumor Protein 53/Ataxia Telangiectasia Mutated Gene