Simultaneous use of multiplex ligation-dependent probe amplification assay and flow cytometric DNA ploidy analysis in patients with acute leukemia.

BACKGROUND: The aim of this work was to simultaneously use multiplex ligation-dependent probe amplification (MLPA) assay and flow cytometric DNA ploidy analysis (FPA) to detect aneuploidy in patients with newly diagnosed acute leukemia. METHODS: MLPA assay and propidium iodide FPA were used to test samples from 53 consecutive patients with newly diagnosed acute leukemia referred to our laboratory for immunophenotyping. Results were compared by nonparametric statistics. RESULTS: The combined use of both methods significantly increased the rate of detection of aneuploidy as compared to that obtained by each method alone. The limitations of one method are somehow countervailed by the other and vice versa. CONCLUSIONS: MPLA and FPA yield different yet complementary information concerning aneuploidy in acute leukemia. The simultaneous use of both methods might be recommended in the clinical setting. © 2017 International Clinical Cytometry Society.

The mutation profile of JAK2, MPL and CALR in Mexican patients with Philadelphia chromosome-negative myeloproliferative neoplasms.

CONTEXT AND OBJECTIVE: By using molecular markers, it is possible to gain information on both the classification and etiopathogenesis of chronic myeloproliferative neoplasias (MPN). METHODS: In a group of 27 Mexican mestizo patients with MPNs, we studied seven molecular markers: the BCR/ABL1 fusion gene, the JAK2 V617F mutation, the JAK2 exon 12 mutations, the MPL W515L mutation, the MPL W515K mutation, and the calreticulin (CALR) exon 9 deletion or insertion. Patients with the BCR/ABL1 fusion gene were excluded. We studied 14 patients with essential thrombocythemia (ET), eight with polycythemia vera (PV), four with primary myelofibrosis (MF), and one with undifferentiated MPN. RESULTS: We found twelve individuals with the JAK2 V617F mutation; five of them had been clinically classified as PV, five as ET, and one as MF. One patient with the MPL W515L was identified with a clinical picture of ET. Five patients with the CALR mutation were identified, four ET and one MF. No individuals with either the MPL W515K mutation or the JAK2 exon 12 mutations were identified. The most consistent relationship was that between PV and the JAK2 V617F mutation (p=.01). CONCLUSIONS: Despite its small size, the study shows much less prevalence of JAK2 mutation in PV, ET and MF, which does not match international data.

Pharmacogenetic selection of volunteers increases stringency of bioequivalence studies; the case of clopidogrel.

Clinical response to clopidogrel varies widely due to under-dosing, drug interactions and intrinsic interindividual differences resulting from genetic polymorphisms. Cytochrome P450-2C19 is the principal enzyme involved in the activation of the prodrug and loss-of-function alleles have been described. Upon expiration of the pharmaceutical patent of clopidogrel, generic manufacturers have started to subject interchangeable formulations to bioequivalence studies. The purpose of the current investigation was to study the effect of selection of volunteers homozygous for the CYP2C19*1 haplotype on the bioavailability of clopidogrel. A regular 2×2 bioequivalence study between two formulations of clopidogrel was performed in volunteers selected and unselected for relevant CYP2C19 haplotypes for the Mexican population. It was found that selection of volunteers homozygous for the CYP2C19*1 haplotype, increased the stringency of bioequivalence statistics and resulted in bioinequivalence of a generic clopidogrel compound that otherwise proved equivalent when tested in an open unselected population. Augmentation of bioequivalence strictness is expected to result from pharmacogenetic selection of volunteers.

Primary thrombophilia in Mexico IX: the glycoprotein IIIa PLA1/A2 polymorphism is not associated with the sticky platelet syndrome phenotype.

INTRODUCTION: The sticky platelet syndrome (SPS) seems to be a common cause of thrombosis, although no molecular substrate to explain platelet hyperaggregability has been found. OBJECTIVE: To analyze an association between the SPS phenotype and the platelet glycoprotein (GP) IIIa PL(A1/A2) (human platelet antigen [HPA]-1a/b) gene polymorphism. METHODS: Along an 18-month period, Mexican mestizo thrombophilic patients were prospectively accrued. The SPS phenotype was assessed by aggregometry, whereas a tetra-primer amplification refractory mutation system (ARMS) polymerase chain reaction analysis was used to detect the PLA1 and PLA2 alleles. RESULTS: A total of 95 individuals with SPS and 127 healthy donors were studied; in 11 of the donors and 16 of the patients with SPS the A2 allele of the GP IIb/IIIA was found, yielding a weak and nonsignificant association (odds ratio 2.14, 95% CI 0.94-4.85). CONCLUSION: In Mexican mestizo patients, the platelet GP IIIa PL(A1/A2) gene polymorphism does not lead to the SPS phenotype.

Primary thrombophilia in México VII: the V617F mutation of JAK2 is not a frequent cause of thrombosis.

The study of the V617F JAK2 gene mutation has been used to identify the presence of an underlying myeloproliferative disorder (MPD) as the cause of unexplained thrombosis. In a group of 77 consecutive Mexican patients with a clinical marker of a primary thrombophilic condition, we looked for this JAK2 mutation and did not find any individual displaying it. Given these results, we conclude that an undetected MPD is a very improbable cause of thromboses in Mexican mestizos, a population where the prevalence of these disorders has been found to be lower than that found in Caucasian populations. Accordingly, it seems that the investigation for the V617F mutation of the JAK2 gene is not mandatory in all Mexican mestizo patients with unexplained thrombophilia and that this genetic study should be reserved for special cases, such as patients with thrombosis in uncommon sites or patients with cell counts suggesting the presence of an underlying MPD.

Methotrexate-induced mucositis in acute leukemia patients is not associated with the MTHFR 677T allele in Mexico.

Methylenetetrahydrofolate reductase (MTHFR) has two common variants with reduced activity due to polymorphisms at nucleotides 677 and 1298. Both affect folate metabolism and thus remethylation of homocysteine, but are also thought to affect nucleotide synthesis and DNA methylation. Methotrexate (MTX), which interrupts folate metabolism, is used in the treatment of a variety of diseases including acute lymphoblastic leukemia (ALL), but exerts in some patients toxic effects on fast dividing tissues such as mucosal epithelia. The enhanced toxicity may be due to cooperative effects between MTX and MTHFR variants. Accordingly, it has been reported that carrying the 677T allele of the MTHFR is a risk factor for MTX-associated mucositis. As in the Mexican population, which is characterized by a high prevalence of the 677T MTHFR variant, several of its commonly associated defects have not been observed, we investigated the relationship between MTX toxicity and the 677T allele. Out of 28 patients with ALL (CC: 2, CT: 10, TT: 16), 16 had episodes of MTX-associated mucositis (CC: 0, CT: 6, TT: 10). Neither at the gene level nor at the genotype level was a significant association with mucositis found. It may be postulated that the risk of higher MTX toxicity in patients with decreased MTHFR activity could be neutralized by the normally folate rich diet in Mexico.

Clearance of the Janus kinase 2 (JAK2) V617F mutation after allogeneic stem cell transplantation in a patient with myelofibrosis with myeloid metaplasia.

A patient with myelofibrosis with myeloid metaplasia displaying the V617F mutation of the JAK2 gene was given an allogeneic stem cell transplantation using a reduced-intensity conditioning regimen. The patient engrafted, and as he became a chimera, the expression of the V617F mutation of the JAK2 gene decreased progressively until its disappearance. Accordingly, the concept of "molecular remission" of the myelofibrosis with myeloid metaplasia could be entertained and added to the categories of response to treatment which have been recently described.

t(8;21) (q22;q22) acute myelogenous leukemia in Mexico: a single institution experience.

We analyze the prevalence and clinical features of a group of patients with t(8;21) (q22;q22) acute myeloblastic leukemia, identified in a single institution in México over a 10-year period. Fifteen patients presented at the Centro de Hematología y Medicina Interna de Puebla from February 1995 to August 2005; only nine were treated and followed in the institution. Median age was 24 years, (range 7-49); there was only one male. According to the French-American-British (FAB) morphological classification of leukemia, the morphology was M2 in four cases, M4 in three cases, M3 in one case and M0 in one. In addition to the myeloid markers, lymphoid markers were identified in 6 patients. Patients were induced to remission with combined chemotherapy and three subsequently underwent bone marrow transplantation (BMT). The median overall and disease-free survival has not been reached, being above 3390 days, the probability of survival at this time was 73%. In this single-center experience in México, we found that the t(8;21) (q22;q22) variant of leukemia was more frequent than in Caucasian populations, that the co-expression of lymphoid markers in the blast cells is very frequent and that this malignancy is associated with a relatively good prognosis.

The Janus Kinase 2 (JAK2) V617F mutation in hematological malignancies in México / La mutación V617F del gen de la cinasa JAK2 en padecimientos hematológicos malignos en México

A new mutation (V617F) affecting the JAK2 gene has been recently described as acquired in patients with myeloproliferative disorders and other myeloid malignancies. Using an amplification refractory mutation system, we investigated this mutation in 70 Mexican mestizo patients with hematological malignancies: 28 cases of acute lymphoblastic leukemia, 17 cases of Phi-positive chronic myelogenous leukemia, 8 patients with acute myelogenous leukemia, 6 patients with chronic lymphocytic leukemia, 6 patients with polycythemia vera (PV), two patients with essential thrombocythemia (ET), one patient with hypereosinophilic syndrome one patient with primary myelofibrosis (MF) and one patient with chronic myelomonocytic leukemia. The mutation was identified in 4 of 6 patients with PV, in one of 2 patients with ET and in the patient with MF. Our data add to the observation that the JAK2 V617F mutation seems to be rather uncommon in myeloid malignancies other than the classic BCR/ABL negative MPD.

Se ha descrito una nueva mutación (V617F) que afecta al gen de la cinasa JAK2 en pacientes con padecimientos mieloproliferativos y otras neoplasias mieloides. Empleando un sistema de amplificación de mutaciones refractarias y reacción en cadena de la polimerasa, investigamos esta mutación en 70 pacientes mestizos mexicanos con neoplasias hematológicas malignas: 28 casos de leucemia aguda linfoblástica, 17 casos de leucemia granulocítica crónica BCR/ABL (+), ocho casos de leucemia aguda mieloblástica, seis casos de leucemia linfocítica crónica, seis casos de policitemia vera (PV), dos casos de trombocitosis primaria (TP), un caso de síndrome hipereosinofílico primario y un caso de mielofibrosis primaria (MF) y un caso de leucemia mielomonocítica crónica. La mutación se identificó en cuatro de seis pacientes con PV, en uno de dos pacientes con TP y en el paciente con MF. Estos datos confirman que esta mutación es infrecuente en neoplasias hematológicas mieloides diferentes a los síndromes mieloproliferativos malignos negativos al BCR/ABL; es probable que esta mutación se convierta en el marcador molecular de la PV.

Molecular characterization of alpha-thalassemia in the Mexican population.

BACKGROUND: alpha-Thalassemia (alpha-Thal) has been poorly characterized at the molecular level in Mexico. METHODS: 106 consecutive individuals identified in Laboratorios Clínicos de Puebla, with either hypochromia (MCH < 24 pg) and/or microcytosis (MCV < 75 fl in women or < 80 fl in man), without iron deficiency, with or without anemia were investigated in this study, along a 16 month-period. alpha and beta-Thal were looked for, the former were characterized at the molecular level. RESULTS: Out of the 106 consecutive cases with hypochromia and/or microcytosis and normal levels of protoporphyrin zinc complex, 48 cases (45.3%) had thalassemia (37 cases of betaThal and 11 cases of alphaThal), whereas in 58 cases (54.7%) a definite diagnosis could not be established. Of the alpha-Thal cases, 8 were heterozygous and two were homozygous for the -alpha3.7 deletion, whereas one case was heterozygous for the alpha2Hph allele. CONCLUSIONS: Only few of the alpha-Thal alleles tested were found, thus the alpha-thalassemic mutations, present in the studied population, seem to be rather heterogeneous.

Molecular characterization of alpha-thalassemia in the Mexican population / Caracterización molecular de talasemia alfa en una población mexicana

Background. α-Thalassemia (α-Thal) has been poorly characterized at the molecular level in Mexico. Methods. 106 consecutive individuals identified in Laboratorios Clínicos de Puebla, with either hypochromia (MCH < 24 pg) and/or microcytosis (MCV < 75 fl in women or < 80 fl in man), without iron deficiency, with or without anemia were investigated in this study, along a 16 month-period, α and β-Thal were looked for, the former were characterized at the molecular level. Results. Out of the 106 consecutive cases with hypochromia and/or microcytosis and normal levels of protoporphyrin zinc complex, 48 cases (45.3%) had thalassemia (37 cases of β-Thal and 11 cases of α-Thal), whereas in 58 cases (54.7%) a definite diagnosis could not be established. Of the α-Thal cases, 8 were heterozygous and two were homozygous for the -α3.7 deletion, whereas one case was heterozygous for the α2Hph allele. Conclusions. Only few of the α-Thal alleles tested were found, thus the α-thalassemic mutations, present in the studied population, seem to be rather heterogeneous.

Antecedentes. En México, la α-talasemia (α-Thal) ha sido pobremente caracterizada a nivel molecular. Mátodos. Se estudiaron 106 individuos consecutivos identificados en los Laboratorios Clínicos de Puebla, con hipocromia (CMH < 24 pg) y lo microcitosis (VCM < 75 fl en mujeres o 80 fl en hombres), sin deficiencia de hierro, con o sin anemia, durante un periodo de 16 meses. Se investigaron α y β-Thal; las primeras fueron caracterizadas a nivel molecular. Resultados. De los 106 casos consecutivos estudiados con hipocromia y/o microcitosis, y niveles normales del complejo de protoporfirina-cinc, 48 casos (45.3%) tenían talasemias (37 de ellos β-Thal y 11 α-Thal), mientras que en 58 casos (54.7%) no pudo establecerse un diagnóstico definitivo. De las talasemias α, ocho casos eran heterocigotos y dos homocigotos para la deleción -α3.7, mientras que sólo un caso resultó heterocigoto para el alelo α2Hph. Conclusiones. De los alelos α-Thal estudiados sólo se encontraron algunos, de lo que se infiere que en la población estudiada esas mutaciones parecen ser bastante heterogáneas.

The Janus Kinase 2 (JAK2) V617F mutation in hematological malignancies in México.

A new mutation (V617F) affecting the JAK2 gene has been recently described as acquired in patients with myeloproliferative disorders and other myeloid malignancies. Using an amplification refractory mutation system, we investigated this mutation in 70 Mexican mestizo patients with hematological malignancies: 28 cases of acute lymphoblastic leukemia, 17 cases of Ph1-positive chronic myelogenous leukemia, 8 patients with acute myelogenous leukemia, 6 patients with chronic lymphocytic leukemia, 6 patients with polycythemia vera (PV), two patients with essential thrombocythemia (ET), one patient with hypereosinophilic syndrome one patient with primary myelofibrosis (MF) and one patient with chronic myelomonocytic leukemia. The mutation was identified in 4 of 6 patients with PV, in one of 2 patients with ET and in the patient with MF. Our data add to the observation that the JAK2 V617F mutation seems to be rather uncommon in myeloid malignancies other than the classic BCR/ABL negative MPD.

HFE-codon 63/282 (H63D/C282Y) gene variants in Mexican Mestizos are not risk factors for leukemia.

BACKGROUND: In some Caucasian populations it has been found that the C282Y hemochromatosis (HFE) gene mutation is a risk factor for the development of leukemia and other malignancies. METHODS: In a group of 50 Mexican mestizo patients and 153 normal controls, the HFE gene mutations H63D and C282Y were studied by means of ARMS-PCR. RESULTS: In the group of patients with leukemia we found a heterozygote for the C282Y mutation, seven heterozygotes for the H63D mutation, a double heterozygote for the H63D / C282Y mutation and 41 normal homozygotes. These data are not different from those observed in normal controls, where the allele frequencies were 0.062 and 0.013 for the H63D and C282Y HFE gene mutations, respectively. CONCLUSIONS: These HFE gene mutations are not risk factors for the development of leukemia in Mexican mestizos.

Treatment of acute promyelocytic leukemia: a single institution experience.

The results of the treatment of 14 patients with promyelocytic leukemia (PML) treated with all trans-retinoic acid (ATRA), combined chemotherapy (CT) and prophylactic prednisone are reported; the median age was 30 years (range 7 - 49). A complete remission (CR) was obtained in 13 / 14 patients (93%). All patients were given ATRA fully as outpatients; the CR was achieved after the administration of ATRA in five patients, whereas in the remaining eight, CT was required to achieve it. There were no instances of the ATRA syndrome. One patient relapsed with a PML/RAR-a negative PML 575 days after achieving the CR, failed to respond again to ATRA and died. The median overall (OS) and disease free survival (DFS) has not been reached, being above 4,000 days, whereas the 12-month DFS was 93%, the three and five years DFS being 85%. The treatment employed differs from others in: Oral prednisone is used prophylactically, ATRA is given on an outpatient basis and adriamycin is used instead of other anthracyclines. The results are similar to those obtained in other centers worldwide and it is possible that the prophylactic administration of prednisone precluded the development of the full-blown ATRA syndrome in this group of patients.

Treatment of acute promyelocytic leukemia: A single institution experience / Tratamiento de la leucemia promielocítica aguda: Experiencia de una sola institución

The results of the treatment of 14 patients with promyelocytic leukemia (PML) treated with all trans-retinoic acid (ATRA), combined chemotherapy (CT) and prophylactic prednisone are reported; the median age was 30 years (range 7 - 49). A complete remission (CR) was obtained in 13 / 14 patients (93%). All patients were given ATRA fully as outpatients; the CR was achieved after the administration of ATRA in five patients, whereas in the remaining eight, CT was required to achieve it. There were no instances of the ATRA syndrome. One patient relapsed with a PML/RAR-a negative PML 575 days after achieving the CR, failed to respond again to ATRA and died. The median overall (OS) and disease free survival (DFS) has not been reached, being above 4,000 days, whereas the 12-month DFS was 93%, the three and five years DFS being 85%. The treatment employed differs from others in: Oral prednisone is used prophylactically, ATRA is given on an outpatient basis and adriamycin is used instead of other anthracyclines. The results are similar to those obtained in other centers worldwide and it is possible that the prophylactic administration of prednisone precluded the development of the full-blown ATRA syndrome in this group of patients.

Se informan los resultados del tratamiento en una sola institución de 14 pacientes con leucemia aguda promielocítica (LAPM) en quienes se empleó la combinación de ácido holotrans-retinoico (ATRA) quimioterapia combinada y prednisona profiláctica. La mediana de edad fue de 30 años (rango 7-49). Se obtuvo remisión completa (hematológica y molecular) (RC) en 13 pacientes (93%); a todos los pacientes se les administró el ATRA de manera ambulatoria. La RC se obtuvo con el ATRA en cinco pacientes; en los demás la RC se obtuvo después de habérseles administrado la quimioterapia con citarabina/adriamicina. No hubo ningún caso de síndrome de ATRA. Un paciente recayó con una LAPM PML/ RAR-a negativa, 575 días después de haber logrado la RC y falleció. Otro paciente recayó 20 meses después de haber logrado la RC y fue rescatado con el mismo esquema de tratamiento; permanece en segunda remisión molecular por más de seis años. La mediana de supervivencia (SV), tanto global como libre de recaídas de todo el grupo, no se ha alcanzado y es mayor de 4,000 días, en tanto que la SV a 12 meses fue de 93% y a tres y cinco años de 85%. El esquema de tratamiento usado difiere de otros en que se usa prednisona oral, se administra el ATRA de manera ambulatoria y se usa adriamicina y no otras antracidinas; los resultados son similares a los obtenidos con otros esquemas parecidos en otros sitios del mundo; es posible que el uso profiláctico de prednisona haya eliminado la ocurrencia del síndrome de ATRA.

Primary thrombophilia in Mexico. V. A comprehensive prospective study indicates that most cases are multifactorial.

Over a 36-month period, 46 consecutive Mexican mestizos with a clinical marker associated with a primary hypercoagulable state were prospectively assessed by searching for the sticky platelet syndrome (SPS), the activated protein C resistance (aPCR) phenotype, coagulation protein C activity and antigen, coagulation protein S, antithrombin III, plasminogen, tissue-type plasminogen activator activity, plasminogen activator inhibitor activity, plasminogen activator inhibitor type 1, IgG and IgM isotypes of antiphospholipid antibodies, homocysteine levels, the factor V gene Leiden, Cambridge, Hong Kong, and Liverpool mutations, the 677 C-->T mutation in the 5,10-methylenetetrahydrofolatereductase (MTHFR), and the G20210A polymorphism in the 3'-untranslated region of the prothrombin gene. Of the 46 consecutive patients prospectively accrued in the study, only 12 (26%) were males, the median age being 38 years (range 10-63 years). In only four individuals (8%) could we not record any abnormality. In 5/42 patients with abnormal results (12%), a single abnormality was recorded, whereas in the remaining 37, two to five co-existing abnormalities were identified. We found 22 (48%) patients with the SPS, 11 (24%) with the aPCR phenotype, 5 (11%) with the factor V Leiden mutation, 7 (15%) with the prothrombin gene mutation, 29 (63%) with the MTHFR gene mutation, 11 (24%) with the factor V HR2 haplotype, 11 (24%) with antiphospholipid antibodies, 4 (9%) with PS deficiency, 6 (13%) with PC deficiency, one with the FV Hong Kong mutation, and one with AT-III deficiency. The results are consonant with the idea that most cases of thrombophilia in Mexico are multifactorial.

More on geographic hematology: the breakpoint cluster regions of the PML/RARalpha fusion gene in Mexican Mestizo patients with promyelocytic leukemia are different from those in Caucasians.

Acute promyelocytic leukemia is characterized the PML/RARalpha chimeric fusion gene, transcript and protein; the breakpoint cluster regions (bcr) in the PML gene may occur in 3 different sites: Intron 6 (bcr1), exon 6 (bcr2) or intron 3 (bcr3). In a 10-year period in a single institution, we studied prospectively the breakpoint cluster regions of the PML/RARalpha fusion gene in 43 Mexican Mestizo patients with APL, and found that the bcr1 represented 62.7%, the bcr2 9.3% whereas the bcr3 27.9%. The prevalence of the bcr1 subtype is significantly higher than that informed in Caucasians and similar to that in Asians; these data are consonant with those described in other Latin-American patients with APL. Since other Asian genetic markers have been found in the Indian component of the Mexican mestizos, it is possible that the Asian immigration into the Americas through the strait of Behring 12,000 years ago may account for a possible genetic susceptibility to suffer certain forms of APL.