[1522] Pyrosequening Analysis for BRAF Mutation in Hairy Cell Leukemia

Dahui Qin, Ling Zhang, Lynn Moscinski, Reza Setoodeh, Shanxiang Shen. Moffitt Cancer Center, Tampa, FL

Background: Hairy Cell Leukemia is a unique entity among leukemic diseases. It has been reported by Brunangelo Falini and Mike Scott etc that hairy cell leukemic cells harbor BRAF mutation detected using Sanger sequencing and high resolution melting curve methods. This discovery offers a possibility of using BRAF mutation as a therapeutic target for hairy cell leukemia. It also offers a possibility of using BRAF mutation as a parameter of differential diagnosis though more investigation on BRAF mutation in different leukemia and lymphoma is needed.
Design: Pyrosequencing method is used to detect BRAF mutations in 7 consecutive hairy cell leukemia cases and 4 marginal zone B cell lymphoma cases in our institution. The targeted sequence is CTAGCTACAGTG, including codon 600 with a dispensing order of CGTATCTGTAG.
Results: BRAF V600E mutation is detected in three out of seven hairy cell leukemia cases. A silent mutation is detected in one of V600E positive cases at codon 598.

All 4 marginal zone B cell lymphoma are negative for BRAF mutation.
Conclusions: Our result is consistent with Brunangelo Falini and Mike Scott groups' data indicating that hairy cell leukemia harbors high frequency of BRAF mutation, which indeed offers an opportunity for molecular targeting therapy. Our positive rate is lower than that in their reports. This could be due to limited case numbers and/or tumor loads in each sample. Generally speaking, pyrosequencing method is more sensitive than Sanger sequencing. Therefore, the sequence method may not be the cause of our lower positive rate. It will be helpful if more investigators start to test their hair cell leukemia cases. It will also be helpful that all investigators use a common method to assess the tumor loads in their samples, which will facilitate data analysis and compare in future.
Category: Hematopathology

Monday, March 19, 2012 1:00 PM

Poster Session II # 223, Monday Afternoon

 

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