Molecular Pathology Laboratory Network

F P53

p53, 17p13-, del(17)(p13,1)

Chronic lymphocytic leukemia (CLL), B-cell prolymphocytic leukemia (PLL), B-cell lymphoproliferative disorder (LPD), Myeloma

Fluorescence in situ Hybridization (FISH)

88367 x2 - Morphometric analysis, in situ hybridization, automated
88368 x2 - Orphometric analysis, in situ hybridization, manual

3 days

• 2.0 mL (min. 1.0 mL) peripheral blood in sodium heparin preferred, EDTA accepted
• 1.0 mL (min. 0.5 mL) bone marrow in sodium heparin preferred, EDTA accepted
• 5 mm^3 fresh tissue in MPLN RPMI media
• 3.0 mL (min. 2.0 mL FNA in MPLN RPMI media
• 10% neutral buffered formalin fixed paraffin embedded tissue

• Peripheral blood and bone marrow stable at 18-25°C for 72 hours
• Fresh tissue or FNA stable at 2-8°C for 72 hours

• Whole blood and bone marrow, ship ambient
• Fresh tissue, FNA or paraffin embedded tissue, ship in a Styrofoam container with an ice pack (Do not allow ice pack to directly contact sample)

Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells; Improper fixative

In a normal cell, two orange, two green signal pattern is observed. An abnormal cell results in the one orange, two green signal pattern.

The p53 tumor suppressor gene is one of the most frequently mutated genes in human cancer with mutations and deletions identified in a wide range of solid tumors and hematological disorders. In hematological disease, p53 gene alterations have been found in 60-80% of Hodgkin disease; 30% of adult T-cell leukemia; 30% of high grade B-cell NHL (rare in low grade NHL); 20-30% of blast crisis CML cases; 5% of MDS; 15% of AML; 15% of CLL; 5-10% of multiple myelomas; and 2% of ALL. Alterations of the p53 gene in hematological malignancies are generally associated with a poor prognosis.

Among solid tumors, p53 is implicated in the Li-Fraumeni syndrome, an inherited cancer-prone disorder often characterized by more than one primary tumor, with tumors often occurring at an earlier age than expected. These include soft tissue sarcomas occurring before the age of 5 years, followed by osteosarcoma, and early onset breast cancer. Among solid tumors, p53 is implicated in cancers of the lung, colon, bladder, breast, skin, esophagus, liver, gastrointestinal tract, cervix, head and neck, ovaries and prostate as well as in melanoma.
FISH can detect this rearrangement in either interphase or metaphase cells.