BCL2/JH, t(14;18) Translocation
The BCL-2 PCR gene rearrangement test is used to detect follicular lymphomas. More than 80% of follicular lymphomas carry a t(14;18) translocation; of which, more than 60% involve the JH locus of the immunoglobulin heavy chain gene on chromosome 14, as well as the major breakpoint region and minor cluster region of the BCL-2 gene from chromosome 18.
The test is performed by using PCR primers spanning the major and minor breakpoint regions and six J segments of the immunoglobulin-heavy chain gene for the translocation detection. Therefore, the assay is able to detect the majority of breakpoints that occur; however, some breakpoints that were out of the primer coverage will not be detected by this method. Additionally, the poor quantity of DNA (caused by inadequate amount of tissue) or poor quality of DNA could also cause absence of t(14;18) translocation amplification. Thus, a negative result does not necessarily exclude the presence of t(14;18) translocation.
Paraffin-embedded tissue; send one tissue block or 4 unstained slides. Ship the specimen at 20° - 25° C. Tissues that are fixed in formalin substitute are unacceptable. Tissue that does not contain lymphocytes is not accepted.
Blood or bone marrow in an EDTA or ACD tube; one 3 mL of blood or 1 mL of bone marrow shipped at 4° C is acceptable. Severely hemolyzed whole blood or clotted/frozen whole blood/bone marrow specimen is unaccepted.
Tissue with a minimum size of 5 mm cube shipped frozen or on ice in RPMI 1640 is accepted.
Cell pellets with at least 1 million cells, shipped at 4° C , are accepted.
- Positive: A (14;18) translocation cell population is detected.
- Negative: A (14;18) translocation cell population is not detected.
- Undetermined: Refer to the interpretation notes.
- QNS: There is not sufficient material to perform the test.