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1.
Allergy ; 75(8): 1927-1938, 2020 08.
Article in English | MEDLINE | ID: mdl-32108361

ABSTRACT

BACKGROUND: In indolent systemic mastocytosis (ISM), several risk factors of disease progression have been identified. Previous studies, performed with limited patient numbers, have also shown that the clinical course in ISM is stable and comparable to that of cutaneous mastocytosis (CM). The aim of this project was to compare the prognosis of patients with ISM with that of patients with CM. METHODS: We employed a dataset of 1993 patients from the registry of the European Competence Network on Mastocytosis (ECNM) to compare outcomes of ISM and CM. RESULTS: We found that overall survival (OS) is worse in ISM compared to CM. Moreover, in patients with typical ISM, bone marrow mastocytosis (BMM), and smoldering SM (SSM), 4.1% of disease progressions have been observed (4.9% of progressions in typical ISM group, 1.7% in BMM, and 9.4% in SSM). Progressions to advanced SM were observed in 2.9% of these patients. In contrast, six patients with CM (1.7%) converted to ISM and no definitive progression to advanced SM was found. No significant differences in OS and event-free survival (EFS) were found when comparing ISM, BMM, and SSM. Higher risk of both progression and death was significantly associated with male gender, worse performance status, and organomegaly. CONCLUSION: Our data confirm the clinical impact of the WHO classification that separates ISM from CM and from other SM variants.


Subject(s)
Mastocytosis, Systemic , Mastocytosis , Bone Marrow , Humans , Male , Mast Cells , Mastocytosis, Systemic/diagnosis , Mastocytosis, Systemic/epidemiology , Prognosis , World Health Organization
2.
Ann R Coll Surg Engl ; 104(5): e153-e155, 2022 May.
Article in English | MEDLINE | ID: mdl-34939844

ABSTRACT

Upper tract urothelial cancers account for 5% of all urothelial cancers. Among these, more than 90% of tumours are located in the renal pelvis, while ureteric tumours are extremely rare. The distal ureter is the most common location, although multifocal implants may also occur. Megaureter is a common cause of obstructive uropathy in neonates and children. Nevertheless, it may be unnoticed, if asymptomatic. Megaureter may be obstructing or refluxing. Long-standing urinary stasis and recurrent urinary tract infection in megaureter may cause chronic irritation of the ureteric mucosa leading to dysplasia and malignancy. We report a 55-year-old man diagnosed with bilateral obstructive megaureter with right lower ureteric urothelial cancer and review the current literature.


Subject(s)
Carcinoma, Transitional Cell , Kidney Neoplasms , Ureter , Ureteral Neoplasms , Ureteral Obstruction , Urinary Bladder Neoplasms , Carcinoma, Transitional Cell/complications , Carcinoma, Transitional Cell/diagnostic imaging , Carcinoma, Transitional Cell/surgery , Child , Female , Humans , Infant, Newborn , Kidney Neoplasms/pathology , Kidney Pelvis/diagnostic imaging , Kidney Pelvis/pathology , Kidney Pelvis/surgery , Male , Middle Aged , Ureter/diagnostic imaging , Ureter/pathology , Ureter/surgery , Ureteral Neoplasms/complications , Ureteral Neoplasms/diagnostic imaging , Ureteral Neoplasms/surgery , Ureteral Obstruction/diagnostic imaging , Ureteral Obstruction/etiology , Ureteral Obstruction/surgery , Urinary Bladder Neoplasms/pathology
3.
Ann R Coll Surg Engl ; 104(6): e183-e186, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35175141

ABSTRACT

A small renal mass is defined as a tumour <4cm. The standard treatment of choice for small renal masses is partial or radical nephrectomy, depending on the tumour anatomy, and has good overall and cancer-specific survival. Its association with lymph node metastasis and inferior vena cava (IVC) thrombus is very uncommon. We describe a case of a right small renal mass with a large metastatic paracaval lymph node with IVC level I thrombus who was treated with right radical nephrectomy with thrombus removal and lymph node excision.


Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Thrombosis , Venous Thrombosis , Carcinoma, Renal Cell/pathology , Carcinoma, Renal Cell/surgery , Humans , Kidney Neoplasms/pathology , Lymphatic Metastasis/pathology , Nephrectomy , Thrombectomy , Thrombosis/pathology , Vena Cava, Inferior/diagnostic imaging , Vena Cava, Inferior/pathology , Venous Thrombosis/complications , Venous Thrombosis/surgery
4.
Ann R Coll Surg Engl ; 104(5): e139-e142, 2022 May.
Article in English | MEDLINE | ID: mdl-34941460

ABSTRACT

Renal cell cancer (RCC) accounts for 3% of all solid malignancies. Synchronous tumour thrombus in the renal vein or inferior vena cava is reported in 4-10% cases and is a surgical challenge. Contemporary imaging modalities that are used to define the presence and extent of venous thrombus include colour Doppler, contrast-enhanced computed tomography and magnetic resonance venography. Surgical management depends upon the degree of tumour thrombus. We report isolated recurrence of RCC in the inferior vena cava 2 years after radical nephrectomy, and discuss its pathophysiology and management.


Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Neoplasms, Second Primary , Neoplastic Cells, Circulating , Thrombosis , Carcinoma, Renal Cell/complications , Carcinoma, Renal Cell/diagnostic imaging , Carcinoma, Renal Cell/surgery , Female , Humans , Kidney Neoplasms/complications , Kidney Neoplasms/diagnostic imaging , Kidney Neoplasms/surgery , Male , Neoplasms, Second Primary/pathology , Neoplastic Cells, Circulating/pathology , Nephrectomy/methods , Retrospective Studies , Thrombectomy , Thrombosis/pathology , Vena Cava, Inferior/diagnostic imaging , Vena Cava, Inferior/pathology , Vena Cava, Inferior/surgery
5.
Nat Microbiol ; 7(9): 1337-1347, 2022 09.
Article in English | MEDLINE | ID: mdl-35927336

ABSTRACT

Early development of the microbiome has been shown to affect general health and physical development of the infant and, although some studies have been undertaken in high-income countries, there are few studies from low- and middle-income countries. As part of the BARNARDS study, we examined the rectal microbiota of 2,931 neonates (term used up to 60 d) with clinical signs of sepsis and of 15,217 mothers screening for blaCTX-M-15, blaNDM, blaKPC and blaOXA-48-like genes, which were detected in 56.1%, 18.5%, 0% and 4.1% of neonates' rectal swabs and 47.1%, 4.6%, 0% and 1.6% of mothers' rectal swabs, respectively. Carbapenemase-positive bacteria were identified by MALDI-TOF MS and showed a high diversity of bacterial species (57 distinct species/genera) which exhibited resistance to most of the antibiotics tested. Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae/E. cloacae complex, the most commonly found isolates, were subjected to whole-genome sequencing analysis and revealed close relationships between isolates from different samples, suggesting transmission of bacteria between neonates, and between neonates and mothers. Associations between the carriage of antimicrobial resistance genes (ARGs) and healthcare/environmental factors were identified, and the presence of ARGs was a predictor of neonatal sepsis and adverse birth outcomes.


Subject(s)
Gastrointestinal Microbiome , Sepsis , Anti-Bacterial Agents , Developing Countries , Drug Resistance, Microbial , Escherichia coli , Female , Humans , Infant , Infant, Newborn , Microbial Sensitivity Tests , Mothers
6.
Hematology ; 23(10): 771-777, 2018 Dec.
Article in English | MEDLINE | ID: mdl-29996726

ABSTRACT

OBJECTIVES: This report presents final results (24 months of follow-up) from the first prospective, national study of frontline nilotinib in chronic myeloid leukemia (CML) patients in Turkey. METHODS: Patients with newly diagnosed Philadelphia chromosome-positive CML in chronic phase (CML-CP; N = 112) received nilotinib 300 mg twice daily. The primary endpoint, which was the cumulative rate of major molecular response (MMR; BCR-ABL1 ≤ 0.1% on the International Scale [BCR-ABL1IS]) by 12 months, was previously reported (66.1% [80% CI, 59.7%-72.0%]). ClinicalTrials.gov identifier NCT01274351 Results: By 24 months, 83.0% of patients achieved MMR, and 50.9% achieved MR4.5 (BCR-ABL1IS ≤0.0032%). Safety results at 24 months were consistent with those at 12 months. No additional deaths or disease progressions to accelerated phase/blast crisis were observed between 12 and 24 months. DISCUSSION: Treatment with nilotinib 300 mg twice daily for 2 years provided high MMR with a good safety/tolerability profile in newly diagnosed CML-CP patients in Turkey. Assessment of MMR across time points showed increasing rates through 18 months, after which as lower rate of increase was observed. The safety profile of nilotinib 300 mg twice daily with 24 months of follow-up was similar to that observed at 12 months, and no new safety concerns were identified. These efficacy and safety findings are consistent with the results from the 12-month analysis of this study and from previous nilotinib studies. These findings support nilotinib as an option for frontline treatment of CML-CP. CONCLUSION: Frontline nilotinib treatment provided sustained efficacy, with good tolerability, over 24 months in newly diagnosed CML-CP patients.


Subject(s)
Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Philadelphia Chromosome , Pyrimidines/administration & dosage , Adult , Aged , Female , Follow-Up Studies , Humans , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Middle Aged , Pyrimidines/adverse effects , Turkey
7.
Hematology ; : 1-7, 2018 Feb 27.
Article in English | MEDLINE | ID: mdl-29486663

ABSTRACT

OBJECTIVES: Nilotinib is a BCR-ABL1 tyrosine kinase inhibitor approved for the treatment of patients with chronic myeloid leukemia in chronic phase (CML-CP). This study was the first prospective evaluation of the efficacy and safety of nilotinib in Turkish patients with newly diagnosed CML-CP. The primary endpoint of the study was the rate of major molecular response (MMR; BCR-ABL1 ≤ 0.1% on the International Scale [BCR-ABL1IS]) by 12 months. METHODS: Patients with newly diagnosed CML-CP were treated with nilotinib 300 mg twice daily. This analysis was based on the first 12 months of follow-up in a 24-month study. This study is registered with ClinicalTrials.gov (NCT01274351). RESULTS: Of 112 patients enrolled, 66.1% (80% CI, 59.7-72.0%) achieved MMR and 22.3% achieved a deep molecular response of MR4.5 (BCR-ABL1IS ≤0.0032%) by 12 months. During the first year of treatment, one patient progressed to blast crisis and two patients died. Safety results were consistent with previous studies. Most adverse events (AEs) were grade 1/2. Most frequently reported nonhematologic AEs of any grade were elevations in bilirubin, alanine aminotransferase, and triglycerides. CONCLUSION: These results support the use of nilotinib 300 mg twice daily as a standard-of-care treatment option for patients with newly diagnosed CML-CP with low and intermediate risk.

8.
Expert Opin Pharmacother ; 17(14): 1851-8, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27501474

ABSTRACT

OBJECTIVE: Nilotinib is a BCR-ABL1 tyrosine kinase inhibitor approved for the treatment of patients with chronic myeloid leukemia in chronic phase (CML-CP). This study was the first prospective evaluation of the efficacy and safety of nilotinib in Turkish patients with newly diagnosed CML-CP. The primary endpoint of the study was the rate of major molecular response (MMR; BCR-ABL1 ≤ 0.1% on the International Scale [BCR-ABL1(IS)]) by 12 months. METHODS: Patients with newly diagnosed CML-CP were treated with nilotinib 300 mg twice daily. This analysis was based on the first 12 months of follow-up in a 24-month study. RESULTS AND CONCLUSIONS: Of 112 patients enrolled, 66.1% (80% CI, 59.7-72.0%) achieved MMR and 22.3% achieved a deep molecular response of MR(4.5) (BCR-ABL1(IS) ≤ 0.0032%) by 12 months. During the first year of treatment, 1 patient progressed to blast crisis and 2 patients died. Safety results were consistent with previous studies. Most adverse events (AEs) were grade 1/2. Most frequently reported nonhematologic AEs of any grade were elevations in bilirubin, alanine aminotransferase, and triglycerides. These results support the use of nilotinib 300 mg twice daily as a standard-of-care treatment option for patients with newly diagnosed CML-CP.


Subject(s)
Antineoplastic Agents/therapeutic use , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Protein Kinase Inhibitors/therapeutic use , Pyrimidines/therapeutic use , Adult , Aged , Female , Fusion Proteins, bcr-abl/antagonists & inhibitors , Humans , Male , Middle Aged , Prospective Studies , Treatment Outcome , Young Adult
9.
Blood Coagul Fibrinolysis ; 16(6): 445-6, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16093736

ABSTRACT

A 36 year-old patient with severe haemophilia A and high-titre inhibitor underwent cataract surgery under topical anaesthesia. Recombinant factor VIIa was used only three times, once before and twice following surgery. Tranexamic acid was given concomitantly. One month after the first successful procedure on the right eye, a second operation was performed on the left eye in the same manner. Both procedures were uneventful. Neither bleeding complications nor any other side effects occurred.


Subject(s)
Blood Coagulation Factor Inhibitors/blood , Blood Loss, Surgical/prevention & control , Cataract Extraction , Cataract , Factor VIII/antagonists & inhibitors , Factor VIIa/administration & dosage , Hemophilia A/surgery , Adult , Cataract/complications , Hemophilia A/blood , Hemophilia A/complications , Humans , Male
10.
Mol Immunol ; 39(7-8): 485-93, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12413700

ABSTRACT

Mutations within the 5'-non-coding region of the bcl-6 gene can occur in lymphomas that originate from germinal centers (GCs), as well as in normal memory and GC B cells. Mutations in the p53 gene occur in 50% of human cancers. Since both bcl-6 and p53 can be mutated in certain circumstances, we investigated the accumulation of mutations in these genes in individual tonsillar B and T cells to determine whether the mutations exhibited a pattern anticipated from the B-cell hypermutation machinery. In tonsillar GC B cells, the overall mutational frequencies in the 5'-non-coding region of the bcl-6 gene was 0.85 x 10(-3)/bp. In contrast, there were no mutations in a region 2.8 kb downstream of the promoter. RGYW (purine, guanine, pyrimidine, A/T) targeting and a significantly lower mutational frequency in nai;ve B and GC founder B cells compared with GC B cells suggested that a similar mutator mechanism was active on Ig genes and this non-Ig gene. The mutational frequency in the exon-7-region of p53 was similar in the GC, memory and nai;ve B-cell subsets (1.02 x 10(-3) to 1.25 x 10(-3)/bp). RGYW/WRCY motifs were not targeted preferentially in the p53 gene. Moreover, a comparable mutational frequency of p53 was noted in tonsillar B and T cells. Hence, mutations in p53 do not appear to be the result of the B-cell hypermutational mechanism.


Subject(s)
B-Lymphocytes/metabolism , DNA-Binding Proteins/genetics , Genes, p53 , Mutation/genetics , Proto-Oncogene Proteins/genetics , Transcription Factors/genetics , Child , Genes, Immunoglobulin , Humans , Palatine Tonsil/immunology , Proto-Oncogene Proteins c-bcl-6
11.
Leuk Lymphoma ; 55(2): 326-30, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23662991

ABSTRACT

Activation induced cytidine deaminase (AID) enzyme, which converts cytosine into uracil and is expressed only by activated B lymphocytes, plays a role in B cells in both the mechanisms of somatic hypermutation (SHM) and class switch recombination (CSR). There are studies showing that AID can cause numerous translocations in different lymphoproliferative diseases. Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of monoclonal B cells in bone marrow and peripheral blood. The predictability and clinical status of B-CLL are difficult to determine. About 30-50% of patients have chromosomal abnormalities. AID, which is thought to create fraction segments for translocations, might also cause deletions in DNA regions of 17p13, 11q22.3, 13q14 and 13q34 that are associated with prognostic implications in patients with CLL. In this study, the AID gene expression in patients with CLL with and without deletions was investigated. When compared to healthy subjects and patients without deletions, increased levels of AID expression in patients with deletions of 17p13, 11q22.3 or 13q14 were found, but not for the 13q34 region. Our results show that AID expression may be associated with deletions in patients with CLL.


Subject(s)
Chromosome Deletion , Cytidine Deaminase/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , RNA, Messenger/genetics , Adult , Aged , Chromosomes, Human, Pair 11/genetics , Chromosomes, Human, Pair 13/genetics , Chromosomes, Human, Pair 17/genetics , Cytogenetic Analysis , Female , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction
12.
J Am Coll Surg ; 208(2): 229-35, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19228534

ABSTRACT

BACKGROUND: Although completion axillary lymph node dissection (CALND) is the gold standard for evaluating axillary status after identification of a positive sentinel lymph node (SLN) in breast cancer, almost 40% to 70% of SLN-positive patients will have negative non-SLNs. To predict non-SLN metastases (NSLNM) in patients with a positive SLN biopsy, four different nomograms have been created. The aim of this study was to evaluate the accuracy of four different nomograms in our SLN-positive breast cancer patients. STUDY DESIGN: We identified 319 patients who had a positive SLN biopsy and CALND at our hospital during an 8-year period. Breast cancer nomograms developed by Memorial Sloan-Kettering Cancer Center, Tenon Hospital, Cambridge University, and Stanford University were used to calculate the probability of NSLNM. The area under the receiver operating characteristics curve was calculated for each nomogram, and values greater than 0.70 were accepted as demonstrating considerable discrimination. RESULTS: One hundred seven of 319 patients (33.5%) had positive axillary NSLNM. The mean number of SLNs was 2.01 (range, 1 to 11 nodes), and the mean number of positive SLNs was 1.44 (range, 1 to 9 nodes). The area under the curve values were 0.70, 0.69, 0.69, and 0.64 for the Memorial Sloan-Kettering Cancer Center, Tenon, Cambridge, and Stanford models, respectively. CONCLUSIONS: We found that the Memorial Sloan-Kettering Cancer Center nomogram was more predictive than the other nomograms, but the Cambridge model and the Tenon model reached borderline values for accurate prediction. Nomograms developed at other institutions should be used with caution when counseling patients about the risk of additional nodal disease.


Subject(s)
Breast Neoplasms/pathology , Lymph Nodes/pathology , Nomograms , Sentinel Lymph Node Biopsy , Adult , Aged , Axilla , Breast Neoplasms/surgery , Female , Humans , Lymph Nodes/surgery , Lymphatic Metastasis , Middle Aged , Predictive Value of Tests , Probability , ROC Curve , Reproducibility of Results
13.
Eur J Trauma Emerg Surg ; 35(4): 378, 2009 Aug.
Article in English | MEDLINE | ID: mdl-26815053

ABSTRACT

BACKGROUND AND AIMS: We aimed to evaluate the independent factors of the treatment of penetrating colon injuries in a teaching and research hospital in light of some of the most commonly cited considerations affecting the decision as to whether to perform primary repair or divert. METHODS: Hospital records of patients between January 2004 and January 2007 were reviewed retrospectively. Fifty-seven patients were included and divided into two groups. Group A consisted of patients (n = 43) who had primary repair or resection and anastomosis, and Group B consisted of patients (n = 14) who had diverting colostomy. The degree of fecal contamination was assessed by reviewing the detailed operative dictation. The type of colon injury, as determined from the colon injury scale (CIS) of the American Association for the Surgery of Trauma (AAST), and the penetrating abdominal trauma index (PATI) were recorded. RESULTS: Age, sex, presence of shock on admission, location of the injury, and colon-related or non-colonrelated complications between the two groups were not significant. Stab or gunshot injury, operation time, degree of fecal contamination (grade 1/2/3), transfusion, PATI score, hospital stay, and associated organ injury were significantly different in the two groups (p < 0.05). CONCLUSION: Despite the fact that CIS, fecal contamination, transfusion, PATI and delayed operation affect the decision about the procedure, primary repair can be performed safely on patients with penetrating colon injuries.

14.
J Allergy Clin Immunol ; 115(6): 1155-61, 2005 Jun.
Article in English | MEDLINE | ID: mdl-15940128

ABSTRACT

BACKGROUND: Mast cells and basophils share similar morphologic and functional properties; however, it is not known whether they are derived from a bilineage (basophil/mast cell)-restricted progenitor. OBJECTIVE: To assess whether basophils and mast cells are derived from common committed progenitors using the c-kit D816V mutation as a biologic signature. METHODS: The D816V c-kit mutation found in mast cells of patients with systemic mastocytosis is used as a trackable genetic marker to assess the lineage relationship between mast cells and basophils. Blood and bone marrow aspirates were collected from 33 consecutive patients with mastocytosis with different disease severity. Peripheral blood basophils, monocytes and neutrophils were sorted by immunomagnetic beads. Presence of the D816V c-kit mutation was analyzed by restriction fragment length polymorphism in the genomic DNA and mRNA from sorted cells in all patients and in the genomic DNA of individual basophils of 1 patient. RESULTS: The c-kit D816V mutation was detectable in basophils of 5 patients (15%). All 5 patients had the c-kit mutation also detectable in monocytes and thus had multilineage involvement. Single cell analysis of the genomic DNA in 1 patient showed a similar degree of clonal expansion in basophils, monocytes, and neutrophils. Mutated c-kit was expressed at the mRNA level in all 5 patients. There was no difference in surface Kit expression levels in basophils. CONCLUSION: Basophils carrying the D816V c-kit mutation in mastocytosis were detected only in the context of a multilineage involvement. These results argue against the presence of a bilineage-restricted committed progenitor for mast cells and basophils.


Subject(s)
Basophils/metabolism , Cell Lineage/genetics , Mast Cells/metabolism , Mastocytosis/genetics , Mutation , Stem Cell Factor/genetics , Basophils/immunology , Humans , Mast Cells/immunology , Mastocytosis/blood , Mastocytosis/immunology , Polymorphism, Restriction Fragment Length , Stem Cell Factor/analysis , Stem Cell Factor/metabolism
15.
J Immunol ; 169(7): 3825-30, 2002 Oct 01.
Article in English | MEDLINE | ID: mdl-12244178

ABSTRACT

To determine the possible role of polymerase eta (pol eta) in somatic hypermutation of B cells, a mutational analysis of 24 nonproductive rearrangements from a patient with xeroderma pigmentosum variant with a defect in pol eta was conducted. Although the mutational frequency of A and T bases decreased in WA (A/T, A) motifs, regardless of their RGYW (purine, G; pyrimidine, A/T) context, the overall mutational frequency of A or T bases was not affected. Moreover, the overall mutational frequency of the sequences examined was not decreased. There was an apparent increase in the number of insertions and deletions. The results are consistent with the conclusion that pol eta specifically targets WA motifs. However, its overall contribution to the somatic hypermutational process does not appear to be indispensable and in its absence other mechanisms maintain mutational activity.


Subject(s)
DNA-Directed DNA Polymerase/genetics , Genetic Variation , Sequence Analysis, DNA , Somatic Hypermutation, Immunoglobulin/genetics , Xeroderma Pigmentosum/enzymology , Xeroderma Pigmentosum/genetics , Base Pair Mismatch/genetics , DNA-Directed DNA Polymerase/analysis , DNA-Directed DNA Polymerase/physiology , Gene Rearrangement, B-Lymphocyte, Heavy Chain , Germ-Line Mutation , Humans , Immunoglobulin Heavy Chains/genetics , Immunoglobulin Variable Region/genetics , Male , Middle Aged , Mutagenesis, Insertional , Repetitive Sequences, Nucleic Acid/genetics , Sequence Analysis, DNA/methods , Sequence Deletion
16.
Blood ; 103(8): 3222-5, 2004 Apr 15.
Article in English | MEDLINE | ID: mdl-15070706

ABSTRACT

Mutational analysis of the c-kit gene in a patient with a previously undescribed variant of mast cell disease revealed a germline mutation, Phe522Cys, within the transmembrane portion of the Kit receptor protein. Transfection experiments revealed that the mutation caused ligand-independent autophosphorylation of Kit, which was inhibited by the tyrosine kinase inhibitor imatinib mesylate. The patient's bone marrow biopsy and aspirate displayed unique pathologic features with the presence of excessive numbers of mature-appearing mast cells and absence of aberrant mast cell surface expression of CD2, CD25, and CD35. Therapy with imatinib mesylate resulted in a dramatic improvement in mast cell burden and clinical symptoms. These results highlight the significance of the transmembrane region of Kit in activation of the molecule and its importance in mast cell development and suggest a role for screening for transmembrane c-kit mutations in patients with mastocytosis in association with the decision to use imatinib mesylate.


Subject(s)
Antineoplastic Agents/therapeutic use , Germ-Line Mutation , Mastocytosis, Systemic/drug therapy , Mastocytosis, Systemic/genetics , Piperazines/therapeutic use , Proto-Oncogene Proteins c-kit/genetics , Pyrimidines/therapeutic use , Adult , Amino Acid Substitution , Benzamides , Bone Marrow/pathology , Female , Humans , Imatinib Mesylate , In Vitro Techniques , Mast Cells/drug effects , Mast Cells/pathology , Mastocytosis, Systemic/pathology
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