Frequency of calreticulin mutation in untreated chronic lymphocytic leukemia patients

Chronic Lymphocytic Leukemia is the most common leukemia of adulthood in western countries which is the disease of clonal malign mature B lymphocytes. Ethyology is uncertain and no genetic mutation is found as the reason for CLL yet. Mutation analysis is performed for diagnostic, prognostic and therapeutical purposes for many years now. Recently mutational status of CLL patients was found to be an important factor for selecting the type of therapy. Calreticulin is a multifunctional protein which mainly serves as a calcium binder in ER and chaperone for many proteins. Many malignancies are found to be related to calreticulin. CALR gene is coding calreticulin and CALR mutations are commonly detected in myeloproliferative diseases. All CALR mutations are insertion or deletion mutations of exon 9. There is limited information about the relationship of CRT and lymphoproliferative diseases. The purpose of this study was to analyse CALR mutation status of CLL patients. The sample of this study consists of 39 CLL diagnosed patients attending to Hematology Department of Dokuz Eylul University who were not treated with cytotoxic agents before. White blood cells were collected from peripheral blood samples, DNA was isolated and copies were multiplied by PCR. Sequence analysis was performed for the exon 9 region. None of the CLL patients had CALR exon 9 mutation. Additional data was collected from patient hospital records. The total number of male patients was 21(53,84%) and female patients was 18(46,16%) respectively. Male vs. Female ratio was 1,16. Most of the patients were Binet stage A (69,24%) and stage B (28,2%) at the time of diagnosis. Only one patient was in Binet C group. Mean age for the time of diagnosis was 56. The data of other important mutations shown to be important for CLL was not enough. New studies with larger patient numbers may be useful for better information. Key words: Chronic Lymphocytic Leukemia, calreticulin, CALR mutation