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Circulating blasts or myeloid precursor cells in peripheral blood can predict success of cytogenetic analysis
Leukemia Research 33 (2009) e75–e76
Contents lists available at ScienceDirect
Leukemia Research journal homepage: www.elsevier.com/locate/leukres
Letter to the Editor Circulating blasts or myeloid precursor cells in peripheral blood can predict success of cytogenetic analysis
Table 1 Comparison of 100 cell manual differential counts and chromosome analysis success. Differential analysis
Cytogenetic analysis of hematologic malignancies is widely performed on bone marrow (BM) or peripheral blood (PB) samples. Previous studies have shown that that the proportion of PB samples that yield a suitable number of metaphase cells for analysis is less than BM samples with the success dependent on the presence of circulating blasts or progenitor cells [1]. To identify predictors of successful PB chromosome analysis, we attempted to determine whether detection of myeloid precursor cells by manual differential count analysis can be used to predict success of chromosome analysis of unstimulated PB. After Institutional Review Board (IRB) approval, a prospective study was performed on 114 consecutive PB specimens submitted to the Cytogenetics Laboratory from patients diagnosed with or suspected of a neoplastic disorder between July and October 2007. The Cytogenetics Laboratory is a reference laboratory and the samples studied were from 14 Mayo Clinic and 100 non-Mayo Clinic patients. One heparinized tube containing PB was received on each patient; a blood smear was made and a 100 cell manual differential count analysis was performed by the Hematolopathology Laboratory. The specimen was also submitted for conventional chromosome analysis following standard cell culture and analysis protocols. In addition fluorescence in situ hybridization (FISH) analysis was requested on 25 samples. Other than the indication for testing included on the test request form, no other clinical information or laboratory testing results were available on the non-Mayo clinic patients. Cytogenetic analysis results were categorized as: unsuccessful (0–4 normal and no abnormal metaphases), normal (≥5 normal metaphases) and abnormal (≥2 abnormal metaphases). Success was defined when a minimum of five normal metaphase cells or two abnormal cells were available for analysis. Manual differential counts on PB smears were categorized by the presence of blasts (1–100%), myeloid precursor cells (or left shift; 1–45% metamyelocytes, myelocytes, or promyelocytes but no blasts), left shift with blasts, relative lymphocytosis (>52%), or a normal differentia (no blasts, left shift or lymphocytosis). Of the 114 PB cases in this study, chromosome analysis was successful in 81 cases and of those, 38 were normal and 43 had an abnormal result (Table 1). A cytogenetic abnormality was identified in 43/84 (52%) samples in which blast cells or myeloid precursors were observed. Of 30 cases where no circulating blasts or myeloid precursor cells were observed, the cytogenetic results were either normal (5 cases) or unsuccessful (25 cases). An abnormal FISH result was observed in 2/14 samples with a normal chromosome result and 6/11 where cytogenetic studies were unsuccessful.
0145-2126/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.leukres.2008.11.022
Chromosome analysis results Unsuccessful
Normal
Abnormal
% Abnormal
Blasts without left shift (n = 9) Left shift and blasts (n = 41) Left shift without blasts (n = 34) Relative lymphocytosis (n = 11) Normal (n = 19)
1 1 6 10 15
1 15 17 1 4
7 25 11 0 0
78 61 32 0 0
Total
33
38
43
38
Hussein et al. demonstrated that in patients with myelofibrosis the results of chromosome analysis from PB and BM were concordant [2]. It was suggested that PB could be considered an alternative sample but additional studies were warranted to change clinical practice. Our findings are consistent with those of a retrospective study of 242 patient samples, which suggested that for some hematologic disorders, PB chromosome analysis was appropriate for patients with a significant number of blasts or circulating myeloid precursor cells (>0.1 × 109 cell/L) [3]. Tefferi et al. demonstrated that FISH testing yielded equivalent results in BM aspirate and PB samples [4]. FISH remains a valuable tool in monitoring the PB for rearrangements associated chronic myelogenous leukemia and detecting PML/RARA fusion in newly diagnosed acute promyelocytic leukemia [5,6]. For patients with CLL, FISH analysis is considered the preferred method for identifying a clinically significant abnormality [7]. PB samples with left shift or blasts are significantly more likely to yield cytogenetic preparations suitable for analysis. Performing a manual PB differential count on samples prior to submission for chromosome studies can be used to predict success of unstimulated peripheral blood chromosome analysis success, and to decide whether to submit PB or BM for testing. It can be used to reduce unnecessary testing effort and medical costs when the likelihood of identifying a chromosome abnormality is low. Contributions A.E. Wiktor and D.L. Van Dyke designed the study, reviewed cytogenetic analysis, interpreted and analyzed the data and wrote the co-authored manuscript. C.A. Hanson analyzed the hematologic data and provided critical manuscript review. J. Hodnefield performed the manual differential analysis. K. Hussein and A. Tefferi contributed to the manuscript review.
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Letter to the Editor / Leukemia Research 33 (2009) e75–e76
Conflict of interest None. References [1] Weinkauff R, Estey EH, Starostik P, Hayes K, Huh YO, Hirsch-Ginsberg C, et al. Use of peripheral blood blasts vs. bone marrow blasts for diagnosis of acute leukemia. Am J Clin Pathol 1999;111:733–40. [2] Hussein K, Ketterling RP, Dewald GW, Van Dyke DL, Mesa R, Hanson CA, et al. Peripheral blood cytogenetic studies in myelofibrosis: overall yield and comparison with bone marrow cytogenetic studies. Leuk Res 2008;32:1597–600. [3] Hussein K, Ketterling RP, Hulshizer RL, Kuffel DG, Wiktor AE, Hanson CA, et al. Peripheral blood cytogenetic studies in hematological neoplasms: predictors of obtaining metaphases for analysis. Eur J Haematol 2008;80:318–21. [4] Tefferi A, Meyer RG, Wyatt WA, Dewald GW. Comparison of peripheral blood interphase cytogenetics with bone marrow karyotype analysis in myelofibrosis with myeloid metaplasia. Br J Haematol 2001;115:316–9. [5] Brockman SR, Paternoster SF, Ketterling RP, Dewald GW. New highly sensitive fluorescence in situ hybridization method to detect PML/RARA fusion in acute promyelocytic leukemia. Cancer Genet Cytogenet 2003;145:144–51. [6] Landstrom AP, Tefferi A. Fluorescent in situ hybridization in the diagnosis, prognosis, and treatment monitoring of chronic myeloid leukemia. Leuk Lymphoma 2006;47:397–402. [7] Aoun P, Blair HE, Smith LM, Dave BJ, Lynch J, Weisenburger DD, et al. Fluorescence in situ hybridization detection of cytogenetic abnormalities in Bcell chronic lymphocytic leukemia/small lymphocytic lymphoma. Leuk Lymph 2004;45:1595–603.
Anne E. Wiktor a,∗ Curtis A. Hanson b Janice M. Hodnefield b Kebede Hussein c Ayalew Tefferi c Daniel L. Van Dyke a a Division of Laboratory Genetics, Cytogenetics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States b Division of Hematopathology, Mayo Clinic, Rochester, MN, United States c Division of Hematology, Mayo Clinic, Rochester, MN, United States ∗ Corresponding
author. Tel.: +1 507 284 8338; fax: +1 507 284 0043. E-mail address: [email protected] (A.E. Wiktor) 29 October 2008 Available online 6 January 2009
Contents lists available at ScienceDirect
Leukemia Research journal homepage: www.elsevier.com/locate/leukres
Letter to the Editor Circulating blasts or myeloid precursor cells in peripheral blood can predict success of cytogenetic analysis
Table 1 Comparison of 100 cell manual differential counts and chromosome analysis success. Differential analysis
Cytogenetic analysis of hematologic malignancies is widely performed on bone marrow (BM) or peripheral blood (PB) samples. Previous studies have shown that that the proportion of PB samples that yield a suitable number of metaphase cells for analysis is less than BM samples with the success dependent on the presence of circulating blasts or progenitor cells [1]. To identify predictors of successful PB chromosome analysis, we attempted to determine whether detection of myeloid precursor cells by manual differential count analysis can be used to predict success of chromosome analysis of unstimulated PB. After Institutional Review Board (IRB) approval, a prospective study was performed on 114 consecutive PB specimens submitted to the Cytogenetics Laboratory from patients diagnosed with or suspected of a neoplastic disorder between July and October 2007. The Cytogenetics Laboratory is a reference laboratory and the samples studied were from 14 Mayo Clinic and 100 non-Mayo Clinic patients. One heparinized tube containing PB was received on each patient; a blood smear was made and a 100 cell manual differential count analysis was performed by the Hematolopathology Laboratory. The specimen was also submitted for conventional chromosome analysis following standard cell culture and analysis protocols. In addition fluorescence in situ hybridization (FISH) analysis was requested on 25 samples. Other than the indication for testing included on the test request form, no other clinical information or laboratory testing results were available on the non-Mayo clinic patients. Cytogenetic analysis results were categorized as: unsuccessful (0–4 normal and no abnormal metaphases), normal (≥5 normal metaphases) and abnormal (≥2 abnormal metaphases). Success was defined when a minimum of five normal metaphase cells or two abnormal cells were available for analysis. Manual differential counts on PB smears were categorized by the presence of blasts (1–100%), myeloid precursor cells (or left shift; 1–45% metamyelocytes, myelocytes, or promyelocytes but no blasts), left shift with blasts, relative lymphocytosis (>52%), or a normal differentia (no blasts, left shift or lymphocytosis). Of the 114 PB cases in this study, chromosome analysis was successful in 81 cases and of those, 38 were normal and 43 had an abnormal result (Table 1). A cytogenetic abnormality was identified in 43/84 (52%) samples in which blast cells or myeloid precursors were observed. Of 30 cases where no circulating blasts or myeloid precursor cells were observed, the cytogenetic results were either normal (5 cases) or unsuccessful (25 cases). An abnormal FISH result was observed in 2/14 samples with a normal chromosome result and 6/11 where cytogenetic studies were unsuccessful.
0145-2126/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.leukres.2008.11.022
Chromosome analysis results Unsuccessful
Normal
Abnormal
% Abnormal
Blasts without left shift (n = 9) Left shift and blasts (n = 41) Left shift without blasts (n = 34) Relative lymphocytosis (n = 11) Normal (n = 19)
1 1 6 10 15
1 15 17 1 4
7 25 11 0 0
78 61 32 0 0
Total
33
38
43
38
Hussein et al. demonstrated that in patients with myelofibrosis the results of chromosome analysis from PB and BM were concordant [2]. It was suggested that PB could be considered an alternative sample but additional studies were warranted to change clinical practice. Our findings are consistent with those of a retrospective study of 242 patient samples, which suggested that for some hematologic disorders, PB chromosome analysis was appropriate for patients with a significant number of blasts or circulating myeloid precursor cells (>0.1 × 109 cell/L) [3]. Tefferi et al. demonstrated that FISH testing yielded equivalent results in BM aspirate and PB samples [4]. FISH remains a valuable tool in monitoring the PB for rearrangements associated chronic myelogenous leukemia and detecting PML/RARA fusion in newly diagnosed acute promyelocytic leukemia [5,6]. For patients with CLL, FISH analysis is considered the preferred method for identifying a clinically significant abnormality [7]. PB samples with left shift or blasts are significantly more likely to yield cytogenetic preparations suitable for analysis. Performing a manual PB differential count on samples prior to submission for chromosome studies can be used to predict success of unstimulated peripheral blood chromosome analysis success, and to decide whether to submit PB or BM for testing. It can be used to reduce unnecessary testing effort and medical costs when the likelihood of identifying a chromosome abnormality is low. Contributions A.E. Wiktor and D.L. Van Dyke designed the study, reviewed cytogenetic analysis, interpreted and analyzed the data and wrote the co-authored manuscript. C.A. Hanson analyzed the hematologic data and provided critical manuscript review. J. Hodnefield performed the manual differential analysis. K. Hussein and A. Tefferi contributed to the manuscript review.
e76
Letter to the Editor / Leukemia Research 33 (2009) e75–e76
Conflict of interest None. References [1] Weinkauff R, Estey EH, Starostik P, Hayes K, Huh YO, Hirsch-Ginsberg C, et al. Use of peripheral blood blasts vs. bone marrow blasts for diagnosis of acute leukemia. Am J Clin Pathol 1999;111:733–40. [2] Hussein K, Ketterling RP, Dewald GW, Van Dyke DL, Mesa R, Hanson CA, et al. Peripheral blood cytogenetic studies in myelofibrosis: overall yield and comparison with bone marrow cytogenetic studies. Leuk Res 2008;32:1597–600. [3] Hussein K, Ketterling RP, Hulshizer RL, Kuffel DG, Wiktor AE, Hanson CA, et al. Peripheral blood cytogenetic studies in hematological neoplasms: predictors of obtaining metaphases for analysis. Eur J Haematol 2008;80:318–21. [4] Tefferi A, Meyer RG, Wyatt WA, Dewald GW. Comparison of peripheral blood interphase cytogenetics with bone marrow karyotype analysis in myelofibrosis with myeloid metaplasia. Br J Haematol 2001;115:316–9. [5] Brockman SR, Paternoster SF, Ketterling RP, Dewald GW. New highly sensitive fluorescence in situ hybridization method to detect PML/RARA fusion in acute promyelocytic leukemia. Cancer Genet Cytogenet 2003;145:144–51. [6] Landstrom AP, Tefferi A. Fluorescent in situ hybridization in the diagnosis, prognosis, and treatment monitoring of chronic myeloid leukemia. Leuk Lymphoma 2006;47:397–402. [7] Aoun P, Blair HE, Smith LM, Dave BJ, Lynch J, Weisenburger DD, et al. Fluorescence in situ hybridization detection of cytogenetic abnormalities in Bcell chronic lymphocytic leukemia/small lymphocytic lymphoma. Leuk Lymph 2004;45:1595–603.
Anne E. Wiktor a,∗ Curtis A. Hanson b Janice M. Hodnefield b Kebede Hussein c Ayalew Tefferi c Daniel L. Van Dyke a a Division of Laboratory Genetics, Cytogenetics Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States b Division of Hematopathology, Mayo Clinic, Rochester, MN, United States c Division of Hematology, Mayo Clinic, Rochester, MN, United States ∗ Corresponding
author. Tel.: +1 507 284 8338; fax: +1 507 284 0043. E-mail address: [email protected] (A.E. Wiktor) 29 October 2008 Available online 6 January 2009