CYP2C19 genotype-phenotype discordance in patients with multiple myeloma leads to an acquired loss of drug-metabolising activity.

PURPOSE: Previous reports indicate that discordance between CYP2C19 genotype and enzyme function occurs in up to 37 % of cancer patients with a range of solid tumours. The aim of this study was to determine whether this acquired loss of function in hepatic CYP2C19 activity also occurs in patients with haematological malignancy. METHODS: CYP2C19 genotype was determined in 25 patients with multiple myeloma using PCR-RFLP analysis for the common allelic variants (*2, 681G>A, rs4244285; *3, 636G>A, rs49486893, and *17, -806C>T, rs12248560). The activity of the enzyme was evaluated using the CYP2C19 probe drug proguanil, and a metabolic ratio used to categorise subjects as extensive or poor metabolisers (PM). RESULTS: No genotypic PM (homozygous null) were detected in this patient cohort. However, CYP2C19 activity was severely compromised in some multiple myeloma patients, resulting in a PM status in 28 % of subjects. Hence, there was significant (p < 0.0001) discordance between the CYP2C19 activity predicted by genotype and the measured phenotype. Discordant CYP2C19 activity did not correlate with any of the pro-inflammatory markers studied. CONCLUSIONS: Acquired loss of CYP2C19 activity occurs in a substantial proportion of patients with multiple myeloma. This indicates that the previously reported phenomenon is not limited to patients with solid tumours. Thus, measurement of CYP2C19 activity rather than CYP2C19 genotype may be more clinically relevant for the determination of whether loss of CYP2C19 function adversely influences the toxicity and efficacy of certain drugs used in medical oncology.

Variability of memory B cell markers in a cohort of common variable immune deficiency patients over 6 months.

Common Variable Immunodeficiency Disorder (CVID) is a complex disorder that predisposes patients to recurrent and severe infections. Immunophenotypic classification schemes were developed to categorize patients with CVID into phenotypic and prognostic groups based on different memory B cell subsets. Whether the B cell subset analysis is stable over time has not been investigated. B cell phenotyping in patients with CVID (n = 15) and sex- and age-matched controls (n = 26) were carried out according to the three B cell classifications. Patients with CVID were evaluated monthly over 6 months. Controls were assessed once during the study. We scored how often each patient was assigned to the same group within each classification. The Freiburg classification assigned patients to the same group at a rate of 73% and the Paris classification at 88%. The EUROclass classification of smB- versus smB+ was at 90%. The two subclassifications [(smB-21low or smB-21norm) and transitional B] were at 87% and 97%, respectively. The level of naïve B cells measured in all patients with CVID during the 6-month evaluation was the most stable B cell subset. We conclude that all classifications systems show considerable variability, but the EUROclass classification was the most reliable scheme for our 15 CVID and 26 healthy cohorts. Our results indicate that phenotypic classifications within CVID will be difficult while there is variability of commonly used assays.

Follicular lymphoma in a X-linked lymphoproliferative syndrome carrier female.

X-linked lymphoproliferative (XLP) syndrome is a rare primary immune-deficiency disorder caused by mutations of the SH2D1A or XIAP genes. Males with the disorder are usually in good health until contracting Epstein-Barr virus (EBV) whereupon the majority of patients die from fulminant infectious mononucleosis, lymphoma or hypogammaglobulinaemia. This report describes a female carrier with an XLP phenotype who was retrospectively identified after her grandson died from the disorder. Subsequent genetic testing identified the patient's mother and affected maternal grandmother as XLP carriers. The family's medical records were significant. The proband had lymphoma at ages 2 and 8 and made a full recovery following treatment. Both the maternal grandmother and uncle died of non-Hodgkin's lymphoma. We were concerned that the XLP carrier mother may be predisposed to lymphoma if the normal X chromosome is skewed towards inactivation. The human androgen receptor assay detected random X chromosome inactivation in the carrier mother. EBV was not detected in the lymphoma tissues of the proband and his grandmother, confirming previous findings that EBV is not always associated with lymphoma in XLP. More significantly, our study highlights the importance of identifying XLP in families with a high incidence of lymphoma.

Interferon-alpha-2b and oral cytarabine ocfosfate for newly diagnosed chronic myeloid leukaemia.

BACKGROUND: Treatment with interferon and subcutaneous cytarabine produces superior cytogenetic responses in chronic myeloid leukaemia (CML) than treatment with interferon alone, but at the expense of greater toxicity. Cytarabine ocfosfate (YNK01) is an oral precursor of cytarabine that may overcome some of the inconvenience and toxicities associated with subcutaneous cytarabine administration. PATIENTS AND METHODS: We studied the efficacy and tolerability of combination therapy with interferon-alpha-2b and YNK01 in patients with newly diagnosed, untreated CML. Forty patients were treated with interferon-alpha-2b (5 MU/m2/day) plus monthly courses of YNK01 (600 mg/day for 10 days) for 1 year. RESULTS: The 6-month complete haematological response rate was 63% and the 1-year major cytogenetic response rate was 30%, with 10% of cytogenetic responses being complete. With a median follow-up of 57 months, the estimated 5-year overall survival was 86% (95% confidence interval 70% to 94%). Treatment tolerability was poor, with toxicity leading to discontinuation of one or both drugs in 60% of cases. The median daily dose of interferon alpha-2b was 7.75 MU and the median dose of YNK01 was 600 mg/day for each 10-day treatment cycle. CONCLUSIONS: Interferon-alpha-2b and YNK01 produce cytogenetic responses comparable to those achieved with interferon-alpha-2b and parenteral cytarabine, although toxicity was excessive. Alternate dosing strategies may enhance the tolerability of YNK01.

Imatinib produces significantly superior molecular responses compared to interferon alfa plus cytarabine in patients with newly diagnosed chronic myeloid leukemia in chronic phase.

We analyzed molecular responses in 55 newly diagnosed chronic-phase chronic myeloid leukemia (CML) patients enrolled in a phase 3 study (the IRIS trial) comparing imatinib to interferon-alfa plus cytarabine (IFN+AraC). BCR-ABL/BCR% levels were measured by real-time quantitative RT-PCR and were significantly lower for the imatinib-treated patients at all time points up to 18 months, P<0.0001. The median levels for imatinib-treated patients continued to decrease and had not reached a plateau by 24 months. A total of 24 IFN+AraC-treated patients crossed over to imatinib. Once imatinib commenced, the median BCR-ABL/BCR% levels in these patients were not significantly different to those on first-line imatinib for the equivalent number of months. The incidence of progression in imatinib-treated patients, defined by hematologic, cytogenetic or quantitative PCR criteria, was significantly higher in the patients who failed to achieve a 1 log reduction by 3 months or a 2 log reduction by 6 months, P=0.002. A total of 49 patients were screened for BCR-ABL kinase domain mutations. Mutations were detected in two imatinib-treated patients who crossed over from IFN+AraC and both lost their imatinib response. In conclusion, first-line imatinib-treated patients had profound reductions in BCR-ABL/BCR%, which significantly exceeded those of IFN+AraC-treated patients and early measurements were predictive of subsequent response.

Prevalence of factor V Leiden and prothrombin variant G20210A in patients age <50 years with no significant stenoses at angiography three to four weeks after myocardial infarction.

OBJECTIVES: We sought to determine the frequencies of factor V Leiden and prothrombin variant G20210A in patients age <50 years with no significant coronary stenoses three to four weeks after myocardial infarction (MI). BACKGROUND: Factor V Leiden and prothrombin variant G20210A occur frequently in patients with venous thromboembolism. However, the contribution of these mutations to the development of MI requires clarification. METHODS: The frequencies of factor V Leiden and prothrombin variant G20210A were determined in 41 patients age <50 years who had "normal" or "near normal" coronary arteries (no stenosis >50%) at angiography three to four weeks after MI (the study group) and compared with those in 114 patients who had at least one angiographic stenosis >50% after MI (the control group). Patients age > or =50 years with, or without, stenoses were also studied. RESULTS: The frequency of factor V Leiden was 14.6% in patients age <50 years in the study group compared with 3.6% in patients in the control group (odds ratio [OR] 4.7 [95% confidence interval (CI) 1.3-17.7], p = 0.02). The frequency of the prothrombin variant G20210A was 7.3% in the study group compared with 1.8% in the control group (OR 4.4 [95% CI 0.7-27.5], p = 0.12). One or both mutations were present in 8 of the 41 patients (19.5%) age <50 years in the study group compared with 6 of the 114 patients (5.5%) in the control group (OR 4.4 [95% CI 1.4-13.5], p = 0.01). In all 271 patients (irrespective of age) with normal arteries, the frequency of factor V Leiden was 11.7% (7/60) compared with 4.3% (9/211) in patients with at least one >50% stenosis (OR 2.9 [95% CI 1.1-8.3], p = 0.04), and the frequency of prothrombin variant G20210A was 6.7% (4/60) compared with 1.4% (3/211) (OR 4.9 [95% CI 1.1-22.8], p = 0.04), respectively. CONCLUSIONS: The frequencies of factor V Leiden and/or prothrombin variant G20210A are increased in patients age <50 years with normal or near normal coronary arteries after MI.

A 20.7 kb deletion within the factor VIII gene associated with LINE-1 element insertion.

Large deletions within the factor VIII gene account for approximately 5% of the mutations causing haemophilia A. The characterization of such mutations can provide insights into the molecular mechanisms of these and other deletions in man. We have analyzed a 20.7 kb deletion spanning exons 15 to 20 within the factor VIII gene in a patient with severe haemophilia A. Long range PCR was used to investigate the extent of the deletion and to provide a template for sequencing across the deletion breakpoint. A 38-base insertion homologous to the 3' region of a LINE-1 (L1) element was detected at the breakpoint of the deletion. Normal sequence at the 5' breakpoint in intron 14 was homologous to an L1 flanking region and normal sequence at the 3' breakpoint in intron 20 was homologous to an adjacent sequence within the same L1 flanking region. A molecular mechanism for the deletion involving retrotransposition of a readthrough product of an L1 element plus its 3' flanking region is suggested.

Successful allogeneic bone marrow transplant for chronic myeloid leukaemia despite previous interferon-induced cardiomyopathy.

We report a patient with CML who developed a reversible dilated cardiomyopathy with cardiac failure following 10 months of IFN therapy. Despite the previous cardiomyopathy, he tolerated subsequent allogeneic BMT without any adverse cardiac events. Reversible IFN-induced cardiomyopathy should not be considered a contraindication to bone marrow transplantation.

A comparison of the effects of oral prednisone and inhaled beclomethasone dipropionate on circulating leukocytes.

BACKGROUND: While the side effects of oral glucocorticoids are well recognised there is debate about the systemic effects of high doses of inhaled glucocorticoids such as beclomethasone dipropionate and how these compare with the effects of oral prednisone. AIMS: To compare the effects of different doses of oral prednisone and inhaled beclomethasone dipropionate (BDP) on changes in circulating leukocytes. METHODS: Changes in different subsets of circulating leukocytes were measured as an index of the systemic effects of inhaled BDP and oral prednisone. We compared the effects of inhaled placebo and 500 and 1000 micrograms of inhaled BDP with oral placebo and 2.5, 5 and 10 mg of prednisone in eight healthy volunteers. Leukocyte numbers were measured before and four hours after each dose of medicine. RESULTS: Compared with inhaled placebo, 1000 micrograms of inhaled BDP led to a significant increase in neutrophils as a percentage of the total white count (p < 0.05) and a significant decrease in the total lymphocyte number (p < 0.05) and in the number of CD4 lymphocytes (p < 0.05). For 1000 micrograms BDP the increase in the % neutrophil count was 8.55% (95% CI 5.17 to 11.93) and the fall in lymphocyte numbers was -0.14 x 10(9)/L (95% CI 0.06 to -0.34) while 2.5 mg prednisone led to an increase in the % neutrophil count of 9.31% (95% CI 5.82 to 12.80) and a fall in lymphocyte numbers of -0.07 x 10(9)/L (95% CI 0.05 to -0.19). CONCLUSIONS: The systemic effects of 1000 micrograms inhaled BDP and 2.5 mg of prednisone are similar.

Colorectal neoplasms detected colonoscopically in at-risk members of colorectal cancer families stratified by the demonstration of DNA microsatellite instability.

This study compared colonoscopic findings in families meeting the Amsterdam criteria (A) for hereditary non-polyposis colorectal cancer (HNPCC) but stratified according to whether the familial cancers showed DNA microsatellite instability. DNA was extracted from paired samples of normal and cancer, and microsatellite instability was analysed at up to six loci. Families were termed replication error positive (RER+) when at least 50% of tumours tested per family were positive. Of 26 families studied 17 were RER+ and 9 were RER-. Cancers in the A/RER- families showed no right-sided predilection (P < 0.001). Colonoscopies have been performed on 182 at-risk members of A/RER+ families and 60 members of A/RER- families. More of the at-risk members of A/RER-families were found to have adenomas at colonoscopy (P = 0.095), but these were smaller than those of A/RER+ families (P = 0.19). The adenoma:carcinoma ratio was twice as high in A/RER- families (13:1) as in A/RER+ families (7:1). One of the A/RER- families had hyperplastic polyposis. The others do not appear to have attenuated familial adenomatous polyposis and are similar to the adenoma families or late-onset colorectal cancer families described by others. This study illustrates the importance of molecular technology in separating HNPCC from syndromes with overlapping phenotypes.

Familial giant hyperplastic polyposis predisposing to colorectal cancer: a new hereditary bowel cancer syndrome.

A mother and five of her ten offspring developed colonic cancers, the mother and one of the offspring being younger than 50 years of age at diagnosis. Despite fulfilling the Amsterdam criteria for hereditary non-polyposis colorectal cancer (HNPCC), several features pointed towards the possibility that this represented a different syndrome of familial cancer. Most notable was the presence of large, multiple hyperplastic polyps and mixed polyps in four of the subjects whose pathology was available for review. In addition, three of the four subjects had cancers that were negative for DNA replication errors (RER-). The subject with an RER+ cancer had a second RER+ cancer and three adenomas, one in contiguity with the second cancer. This subject also had multiple, large hyperplastic polyps, thereby combining hyperplastic polyposis and a proneness to multiple RER+ tumours. One of the hyperplastic polyps was also RER+. Two of five young asymptomatic descendants have been found to harbour multiple colorectal polyps. It is suggested that giant hyperplastic polyposis is a new familial syndrome predisposing to colorectal cancer.

Transformation of essential thrombocythaemia to T cell acute lymphoblastic leukaemia.

Leukaemic transformation of essential thrombocythaemia is a rare event and is usually associated with previous treatment with either alkylating agents or radioactive phosphorous. We describe a patient with essential thrombocythaemia who developed an acute leukaemia of T cell phenotype following hydroxyurea therapy. The T cell phenotype of the blasts suggests the target cell for leukaemic transformation was a pluripotential stem cell.

Factor IX gene mutations in haemophilia B: a New Zealand population-based study.

Haemophilia B (Christmas disease) is an X-linked bleeding disorder resulting from an inherited deficiency of coagulation factor IX activity. Due to the heterogeneity of mutations within the factor IX gene there is a marked clinical variability in disease severity. By applying techniques of mutational analysis and direct sequencing of PCR products it is now potentially possible to determine the pathogenic gene defect in entire haemophilia B populations. We report here characterization of the factor IX gene defect in all the haemophilia B patients in New Zealand as part of a nationwide approach towards providing efficient and cost-effective haemophilia B genetic counselling services for these families. Twenty-six different mutations were identified in 32 unrelated haemophilia B families. Three defects at nucleotide positions +8,6659 and 17696 are novel mutations which have not been reported by other laboratories. A PCR-based diagnostic screening test for direct mutational analysis could be performed in most cases; 17 of the 26 mutations altered a restriction enzyme recognition sequence and, with the exception of the total gene deletion, base changes not affecting a restriction enzyme site could be detected by allele-specific PCR.

Diagnostic use of microsatellite instability in hereditary non-polyposis colorectal cancer.

50 families with a history of colorectal cancer were divided according to whether criteria for hereditary non-polyposis colorectal cancer (HNPCC) were fulfilled totally (A, n = 19) or partly (B, n = 31) and stratified by the demonstration that at least half the cancers tested per family were positive for DNA replication errors (RER+). Accepted clinical and pathological characteristics of HNPCC were found to cluster within 12 A/RER+ families in which the mean number of affected individuals per family was 10.1. Reliance upon clinical data alone may result in over-diagnosis of HNPCC, in small families who just meet the minimum criteria, whereas underdiagnosis is rare. The criteria could be refined by inclusion of RER status.