A Nine-Gene Expression Signature Distinguished a Patient with Chronic Lymphocytic Leukemia Who Underwent Prolonged Periodic Fasting.

Background and Objectives: This study aimed to investigate the causes of continuous deep fluctuations in the absolute lymphocyte count (ALC) in an untreated patient with Chronic Lymphocytic Leukemia (CLL), who has had a favorable prognosis since the time of diagnosis. Up until now, the patient has voluntarily chosen to adopt a predominantly vegetarian and fruitarian diet, along with prolonged periods of total fasting (ranging from 4 to 39 days) each year. Materials and Methods: For this purpose, we decided to analyze the whole transcriptome profiling of peripheral blood (PB) CD19+ cells from the patient (#1) at different time-points vs. the same cells of five other untreated CLL patients who followed a varied diet. Consequently, the CLL patients were categorized as follows: the 1st group comprised patient #1 at 20 different time-points (16 time-points during nutrition and 4 time-points during fasting), whereas the 2nd group included only one time point for each of the patients (#2, #3, #4, #5, and #6) as they followed a varied diet. We performed microarray experiments using a powerful tool, the Affymetrix Human Clariom™ D Pico Assay, to generate high-fidelity biomarker signatures. Statistical analysis was employed to identify differentially expressed genes and to perform sample clustering. Results: The lymphocytosis trend in patient #1 showed recurring fluctuations since the time of diagnosis. Interestingly, we observed that approximately 4-6 weeks after the conclusion of fasting periods, the absolute lymphocyte count was reduced by about half. The gene expression profiling analysis revealed that nine genes were statistically differently expressed between the 1st group and the 2nd group. Specifically, IGLC3, RPS26, CHPT1, and PCDH9 were under expressed in the 1st group compared to the 2nd group of CLL patients. Conversely, IGHV3-43, IGKV3D-20, PLEKHA1, CYBB, and GABRB2 were over-expressed in the 1st group when compared to the 2nd group of CLL patients. Furthermore, clustering analysis validated that all the samples from patient #1 clustered together, showing clear separation from the samples of the other CLL patients. Conclusions: This study unveiled a small gene expression signature consisting of nine genes that distinguished an untreated CLL patient who followed prolonged periods of total fasting, maintaining a gradual growth trend of lymphocytosis, compared to five untreated CLL patients with a varied diet. Future investigations focusing on patient #1 could potentially shed light on the role of prolonged periodic fasting and the implication of this specific gene signature in sustaining the lymphocytosis trend and the favorable course of the disease.

Cordycepin (3'dA) Induces Cell Death of AC133+ Leukemia Cells via Re-Expression of WIF1 and Down-Modulation of MYC.

Wnt/ß-catenin signaling is critically required for the development and maintenance of leukemia stem cells (LSCs) in acute myeloid leukemia (AML) by constitutive activation of myeloid regeneration-related pathways. Cell-intrinsic activation of canonical Wnt signaling propagates in the nucleus by ß-catenin translocation, where it induces expression of target oncogenes such as JUN, MYC and CCND1. As the Wnt/ß-catenin pathway is now well established to be a key oncogenic signaling pathway promoting leukemic myelopoiesis, targeting it would be an effective strategy to impair LSC functionality. Although the effects of the adenosine analogue cordycepin in repressing ß-catenins and destabilizing the LSC niche have been highlighted, the cellular and molecular effects on AML-LSC have not been fully clarified. In the present study, we evaluated the potency and efficacy of cordycepin, a selective repressor of Wnt/ß-catenin signaling with anti-leukemia properties, on the AC133+ LSC fraction. Cordycepin effectively reduces cell viability of the AC133+ LSCs in the MUTZ-2 cell model and patient-derived cells through the induction of apoptosis. By Wnt-targeted RNA sequencing panel, we highlighted the re-expression of WIF1 and DKK1 among others, and the consequent downregulation of MYC and PROM1 (CD133) following MUTZ-2 cell exposure to increasing doses of cordycepin. Our results provide new insights into the molecular circuits involved in pharmacological inhibition mediated by cordycepin reinforcing the potential of targeting the Wnt/ß-catenin and co-regulatory complexes in AML.

Occurrence of L1M Elements in Chromosomal Rearrangements Associated to Chronic Myeloid Leukemia (CML): Insights from Patient-Specific Breakpoints Characterization.

Chronic myeloid leukemia (CML) is a rare myeloproliferative disorder caused by the reciprocal translocation t(9;22)(q34;q11) in hematopoietic stem cells (HSCs). This chromosomal translocation results in the formation of an extra-short chromosome 22, called a Philadelphia chromosome (Ph), containing the BCR-ABL1 fusion gene responsible for the expression of a constitutively active tyrosine kinase that causes uncontrolled growth and replication of leukemic cells. Mechanisms behind the formation of this chromosomal rearrangement are not well known, even if, as observed in tumors, repetitive DNA may be involved as core elements in chromosomal rearrangements. We have participated in the explorative investigations of the PhilosoPhi34 study to evaluate residual Ph+ cells in patients with negative FISH analysis on CD34+/lin- cells with gDNA qPCR. Using targeted next-generation deep sequencing strategies, we analyzed the genomic region around the t(9;22) translocations of 82 CML patients and one CML cell line and assessed the relevance of interspersed repeat elements at breakpoints (BP). We found a statistically higher presence of LINE elements, in particular belonging to the subfamily L1M, in BP cluster regions of both chromosome 22 and 9 compared to the whole human genome. These data suggest that L1M elements could be potential drivers of t(9;22) translocation leading to the generation of the BCR-ABL1 chimeric gene and the expression of the active BCR-ABL1-controlled tyrosine kinase chimeric protein responsible for CML.

A novel start-loss mutation of the SH2B3 gene in a family with myeloproliferative neoplasms.

The ever-increasing advances in high-throughput sequencing have broadened our understanding of the genetic pathogenesis of Philadelphia-negative myeloproliferative neoplasms (MPNs). Convergent studies have shown that MPN driver mutations associate with additional mutations found in genes coding for negative regulators of the JAK/STAT signaling, including the SH2B3 (SH2B-adaptor protein 3, also known as LNK). Here, we describe a novel heterozygous start-loss mutation of the SH2B3 gene (c.3G>A, SH2B3M? ) in a consanguineous family characterized by recurrent early onset of JAK2V617F -positive MPNs. The model represented by this pedigree suggests that the SH2B3 could be a predisposing mutation that facilitates the acquisition of driver mutations.

A Nutritional Approach for the Management of Chemotherapy-Induced Diarrhea in Patients with Colorectal Cancer.

This study aimed to determine if dietary modifications using a nutritional regimen could prevent or reduce the incidence of cancer therapy-induced diarrhea in patients with metastatic colorectal cancer and to evaluate the relationship of Vitamin D blood levels with diarrhea severity. Patients with metastatic colorectal cancer were enrolled. A Mediterranean diet, containing some special limitations aiming to reduce the risk of diarrhea, was administered before and during the entire chemotherapy program. Enrolled patients numbering 60/137 (44%) had diarrhea during chemotherapy. Adherence to the diet was high in 36 (26.3%) patients, medium in 94 (68.6%), and low in 7 (5.1%). Mean adherence to the diet was significantly lower in patients who experienced diarrhea with maximum grade 2−3 compared to those who had no diarrhea or grade 1 diarrhea (score = 5.4 ± 1.9 vs. 7.1 ± 1.5, p < 0.001). Patients with higher adherence to the diet had a lower risk of grade 2−3 diarrhea (odds ratio: 0.5 (95% CI: 0.3−0.7, p < 0.001)). In addition, patients who completed a higher number of chemotherapy cycles had an increased risk of grade 2−3 diarrhea (odds ratio: 1.2 (95% CI: 1.0−1.5, p = 0.02)). Of note, a lower level of Vitamin D correlated with an increased risk of G2-G3 diarrhea (p = 0.03). A diet based on vegetables with a controlled fiber content, Mediterranean Modified Healthy Diet (MMHD), is useful to control the incidence of cancer therapy-induced diarrhea.

Role of Diet in the Management of Carcinoid Syndrome: Clinical Recommendations for Nutrition in Patients with Neuroendocrine Tumors.

Nutrition and metabolism are altered in patients with gastroenteropancreatic neuroendocrine tumors, which is related to excessive production of gastrointestinal hormones, peptides, and amines that can cause maldigestion, diarrhea, steatorrhea, and altered gastrointestinal motility. Patients with carcinoid syndrome are at risk of malnutrition due to tryptophan depletion, reduced intake of food, and loss of appetite because of diarrhea and/or flushing. To date, there is limited information on the nutritional issues faced by patients with neuroendocrine tumors, and on what specific recommendations should be made to patients concerning nutrition at various stages of the disease process. Dietary planning should therefore be an integral part of multidisciplinary management for patients with neuroendocrine tumors. Herein, we review current guidance for nutrition in patients with neuroendocrine tumors, focusing on intake of amines and foods to avoid, as well as concurrent medications. We also propose a new and practical food pyramid based on the principles of Mediterranean diet 4.0 that can be easily adapted according to the unmet needs of patients with neuroendocrine tumors at all stages of disease. The overarching goal of the present review is to create greater awareness of nutritional care and considerations that should be given to patients with neuroendocrine tumors.

Nilotinib-induced bone marrow CD34+/lin-Ph+ cells early clearance in newly diagnosed CP-Chronic Myeloid Leukemia: Final report of the PhilosoPhi34 study.

Chronic Myeloid Leukemia is a clonal disorder characterized by the presence of the Ph-chromosome and the BCR-ABL tyrosine-kinase (TK). Target-therapy with Imatinib has greatly improved its outcome. Deeper and faster responses are reported with the second-generation TKI Nilotinib. Sustained responses may enable TKI discontinuation. However, even in a complete molecular response, some patients experience disease recurrence possibly due to persistence of quiescent leukemic CD34+/lin-Ph+ stem cells (LSCs). Degree and mechanisms of LSCs clearance during TKI treatment are not clearly established. The PhilosoPhi34 study was designed to verify the in-vivo activity and timecourse of first-line Nilotinib therapy on BM CD34+/lin-Ph+ cells clearance. Eighty-seven CP-CML patients were enrolled. BM cells were collected and tested for Ph+ residual cells, at diagnosis, 3, 6 and 12 months of treatment. FISH analysis of unstimulated CD34+/lin- cells in CCyR patients were positive in 8/65 (12.3%), 5/71 (7%), 0/69 (0%) evaluable tests, respectively. Per-Protocol analysis response rates were as follows: CCyR 95% at 12 months, MR4.5 31% and 46% at 12 and 36 months, respectively. An exploratory Gene Expression Profiling (GEP) study of CD34+/lin- cells was performed on 30 patients at diagnosis and after, on 79 patients at diagnosis vs 12 months of nilotinib treatment vs 10 healthy subjects. Data demonstrated some genes significantly different expressed: NFKBIA, many cell cycle genes, ABC transporters, JAK-STAT signaling pathway (JAK2). In addition, a correlation between different expression of some genes (JAK2, OLFM4, ICAM1, NFKBIA) among patients at diagnosis and their achievement of an early and deeper MR was observed.

Identification of a Candidate Gene Set Signature for the Risk of Progression in IgM MGUS to Smoldering/Symptomatic Waldenström Macroglobulinemia (WM) by a Comparative Transcriptome Analysis of B Cells and Plasma Cells.

Waldenström Macroglobulinemia (WM) is a B-cell lymphoma characterized by the precursor condition IgM monoclonal gammopathies of undetermined significance (IgM MGUS). We performed a gene expression profiling study to compare the transcriptome signatures of bone marrow (BM) B-cells and plasma cells of 36 WM patients, 13 IgM MGUS cases, and 7 healthy subjects used as controls (CTRLs) by Affymetrix microarray. We determined 2038 differentially expressed genes (DEGs) in CD19+ cells and 29 DEGs genes in CD138+ cells, respectively. The DEGs identified in B-cells were associated with KEGG pathways, mainly involved in hematopoietic cell lineage antigens, cell adhesion/focal adhesion/transmembrane proteins, adherens junctions, Wnt-signaling pathway, BCR-signaling pathway, calcium signaling pathway, complement/coagulation cascade, platelet activation, cytokine-cytokine receptor interactions, and signaling pathways responsible for cell cycle, apoptosis, proliferation and survival. In conclusion, we showed the deregulation of groups of genes belonging to KEGG pathways in the comparison among WM vs. IgM MGUS vs. CTRLs in B-cells. Interestingly, a small set of genes in B-cells displayed a common transcriptome expression profile between WM and IgM MGUS compared to CTRLs, suggesting its possible role in the risk of transformation of IgM MGUS to WM.

FZD6 triggers Wnt-signalling driven by WNT10BIVS1 expression and highlights new targets in T-cell acute lymphoblastic leukemia.

Wnt/Fzd signaling has been implicated in hematopoietic stem cell maintenance and in acute leukemia establishment. In our previous work, we described a recurrent rearrangement involving the WNT10B locus (WNT10BR ), characterized by the expression of WNT10BIVS1 transcript variant, in acute myeloid leukemia. To determine the occurrence of WNT10BR in T-cell acute lymphoblastic leukemia (T-ALL), we retrospectively analyzed an Italian cohort of patients (n = 20) and detected a high incidence (13/20) of WNT10BIVS1 expression. To address genes involved in WNT10B molecular response, we have designed a Wnt-targeted RNA sequencing panel. Identifying Wnt agonists and antagonists, it results that the expression of FZD6, LRP5, and PROM1 genes stands out in WNT10BIVS1 positive patients compared to negative ones. Using MOLT4 and MUTZ-2 as leukemic cell models, which are characterized by the expression of WNT10BIVS1 , we have observed that WNT10B drives major Wnt activation to the FZD6 receptor complex through receipt of ligand. Additionally, short hairpin RNAs (shRNAs)-mediated gene silencing and small molecule-mediated inhibition of WNTs secretion have been observed to interfere with the WNT10B/FZD6 interaction. We have therefore identified that WNT10BIVS1 knockdown, or pharmacological interference by the LGK974 porcupine (PORCN) inhibitor, reduces WNT10B/FZD6 protein complex formation and significantly impairs intracellular effectors and leukemic expansion. These results describe the molecular circuit induced by WNT10B and suggest WNT10B/FZD6 as a new target in the T-ALL treatment strategy.

Nilotinib interferes with cell cycle, ABC transporters and JAK-STAT signaling pathway in CD34+/lin- cells of patients with chronic phase chronic myeloid leukemia after 12 months of treatment.

Chronic myeloid leukemia (CML) is characterized by the constitutive tyrosine kinase activity of the oncoprotein BCR-ABL1 in myeloid progenitor cells that activates multiple signal transduction pathways leading to the leukemic phenotype. The tyrosine-kinase inhibitor (TKI) nilotinib inhibits the tyrosine kinase activity of BCR-ABL1 in CML patients. Despite the success of nilotinib treatment in patients with chronic-phase (CP) CML, a population of Philadelphia-positive (Ph+) quiescent stem cells escapes the drug activity and can lead to drug resistance. The molecular mechanism by which these quiescent cells remain insensitive is poorly understood. The aim of this study was to compare the gene expression profiling (GEP) of bone marrow (BM) CD34+/lin- cells from CP-CML patients at diagnosis and after 12 months of nilotinib treatment by microarray, in order to identify gene expression changes and the dysregulation of pathways due to nilotinib action. We selected BM CD34+/lin- cells from 78 CP-CML patients at diagnosis and after 12 months of first-line nilotinib therapy and microarray analysis was performed. GEP bioinformatic analyses identified 2,959 differently expressed probes and functional clustering determined some significantly enriched pathways between diagnosis and 12 months of nilotinib treatment. Among these pathways, we observed the under expression of 26 genes encoding proteins belonging to the cell cycle after 12 months of nilotinib treatment which led to the up-regulation of chromosome replication, cell proliferation, DNA replication, and DNA damage checkpoint at diagnosis. We demonstrated the under expression of the ATP-binding cassette (ABC) transporters ABCC4, ABCC5, and ABCD3 encoding proteins which pumped drugs out of the cells after 12 months of nilotinib. Moreover, GEP data demonstrated the deregulation of genes involved in the JAK-STAT signaling pathway. The down-regulation of JAK2, IL7, STAM, PIK3CA, PTPN11, RAF1, and SOS1 key genes after 12 months of nilotinib could demonstrate the up-regulation of cell cycle, proliferation and differentiation via MAPK and PI3K-AKT signaling pathways at diagnosis.

Wide-transcriptome analysis and cellularity of bone marrow CD34+/lin- cells of patients with chronic-phase chronic myeloid leukemia at diagnosis vs. 12 months of first-line nilotinib treatment.

BACKGROUND: Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder with heterogeneous biological and clinical features. The biomolecular mechanisms of CML response to tyrosine-kinase inhibitors are not fully defined. OBJECTIVE: We undertook a gene expression profiling (GEP) study of selected bone marrow (BM) CD34+/lin- cells of chronic-phase CML patients at diagnosis and after 12 months of TKI nilotinib to investigate molecular signatures characterizing both conditions.

Clonal architecture of CXCR4 WHIM-like mutations in Waldenström Macroglobulinaemia.

CXCR4(WHIM) somatic mutations are distinctive to Waldenström Macroglobulinaemia (WM), and impact disease presentation and treatment outcome. The clonal architecture of CXCR4(WHIM) mutations remains to be delineated. We developed highly sensitive allele-specific polymerase chain reaction (AS-PCR) assays for detecting the most common CXCR4(WHIM) mutations (CXCR4(S338X C>A and C>G) ) in WM. The AS-PCR assays detected CXCR4(S338X) mutations in WM and IgM monoclonal gammopathy of unknown significance (MGUS) patients not revealed by Sanger sequencing. By combined AS-PCR and Sanger sequencing, CXCR4(WHIM) mutations were identified in 44/102 (43%), 21/62 (34%), 2/12 (17%) and 1/20 (5%) untreated WM, previously treated WM, IgM MGUS and marginal zone lymphoma patients, respectively, but no chronic lymphocytic leukaemia, multiple myeloma, non-IgM MGUS patients or healthy donors. Cancer cell fraction analysis in WM and IgM MGUS patients showed CXCR4(S338X) mutations were primarily subclonal, with highly variable clonal distribution (median 35·1%, range 1·2-97·5%). Combined AS-PCR and Sanger sequencing revealed multiple CXCR4(WHIM) mutations in many individual WM patients, including homozygous and compound heterozygous mutations validated by deep RNA sequencing. The findings show that CXCR4(WHIM) mutations are more common in WM than previously revealed, and are primarily subclonal, supporting their acquisition after MYD88(L265P) in WM oncogenesis. The presence of multiple CXCR4(WHIM) mutations within individual WM patients may be indicative of targeted CXCR4 genomic instability.

Microarray demonstrates different gene expression profiling signatures between Waldenström macroglobulinemia and IgM monoclonal gammopathy of undetermined significance.

Waldenström macroglobulinemia (WM) (symptomatic and indolent) and immunoglobulin M (IgM) monoclonal gammopathy of undetermined significance (IgMMGUS) can be identified based on the bone marrow (BM) infiltration and the existence of symptoms. The purpose of this study was to investigate the biological and genetic characteristics of both disorders comparing the molecular signature of WM versus IgMMGUS using microarray analysis. We investigated BM CD19(+) cells isolated from 21 WM patients and 10 IgMMGUS cases, and CD138(+) BM cells isolated from all of the WM patients and 4 of the IgMMGUS cases. Gene expression profiling of WM versus IgMMGUS CD19(+) cells highlighted 151 differently expressed genes and the comparison with CD138(+) cells demonstrated 43 differently expressed genes in WM versus IgMMGUS. Regulation of transcription, Janus kinase/signal transducer and activator of transcription, PI3K/Akt/mammalian target of rapamycin, mitogen-activated protein kinase signaling pathways are the relevant gene ontology biological processes occurring in CD19(+) cells, and immune response, cell activation, and signaling processes developing in CD138(+) cells mainly distinguish WM and IgMMGUS.

MYD88 L265P in Waldenström macroglobulinemia, immunoglobulin M monoclonal gammopathy, and other B-cell lymphoproliferative disorders using conventional and quantitative allele-specific polymerase chain reaction.

By whole-genome and/or Sanger sequencing, we recently identified a somatic mutation (MYD88 L265P) that stimulates nuclear factor κB activity and is present in >90% of Waldenström macroglobulinemia (WM) patients. MYD88 L265P was absent in 90% of immunoglobulin M (IgM) monoclonal gammopathy of undetermined significance (MGUS) patients. We therefore developed conventional and real-time allele-specific polymerase chain reaction (AS-PCR) assays for more sensitive detection and quantification of MYD88 L265P. Using either assay, MYD88 L265P was detected in 97 of 104 (93%) WM and 13 of 24 (54%) IgM MGUS patients and was either absent or rarely expressed in samples from splenic marginal zone lymphoma (2/20; 10%), CLL (1/26; 4%), multiple myeloma (including IgM cases, 0/14), and immunoglobulin G MGUS (0/9) patients as well as healthy donors (0/40; P < 1.5 × 10(-5) for WM vs other cohorts). Real-time AS-PCR identified IgM MGUS patients progressing to WM and showed a high rate of concordance between MYD88 L265P ΔCT and BM disease involvement (r = 0.89, P = .008) in WM patients undergoing treatment. These studies identify MYD88 L265P as a widely present mutation in WM and IgM MGUS patients using highly sensitive and specific AS-PCR assays with potential use in diagnostic discrimination and/or response assessment. The finding of this mutation in many IgM MGUS patients suggests that MYD88 L265P may be an early oncogenic event in WM pathogenesis.

Gene expression profiling identifies ARSD as a new marker of disease progression and the sphingolipid metabolism as a potential novel metabolism in chronic lymphocytic leukemia.

BACKGROUND: Several studies demonstrated IGVH mutational status and ZAP70 expression as the most relevant prognostic markers in Chronic Lymphocytic Leukemia (CLL), suggesting the separation of two patient subgroups: with good mutated ZAP70 negative (MTZAP70(-) and poor unmutated ZAP70 positive (UMZAP70(+)) prognosis. DESIGN AND METHODS: We determined the gene expression of B cells in 112 CLL patients divided into three classes: class 1 with MTZAP70(-), class 2 with UMZAP70(+), and class 3 included both UMZAP70(-) and MTZAP70(+). RESULTS: We found LPL, AGPAT2, MBOAT1, CHPT1, AGPAT4, PLD1 genes encoding enzymes involved in lipid metabolism overexpressed in UMZAP70(+). In addition, this study identified ARSD, a gene belonging to the sphingolipid metabolism, as a new gene significantly overexpressed in UMZAP70(+) compared to MTZAP70(-). Western blots confirmed that ARSD protein levels were significantly different between the 3 classes of patients and normal controls. Statistical analysis identified a significant correlation between ARSD and IGVH; however, both ARSD protein level and IGVH were independently associated with the need for therapy of CLL patients. CONCLUSIONS: ARSD is a novel prognostic factor as the time to start therapy is shorter in patients with high levels of ARSD protein and sphingolipid metabolism could represent a new biological mechanism in CLL.

ZAP-70, IgVh, and cytogenetics for assessing prognosis in chronic lymphocytic leukemia.

BACKGROUND: New prognostic factors such as IgVh mutational status, ZAP-70 protein expression and cytogenetic abnormalities have shown to offer important prognostic information for patients with chronic lymphocytic leukemia (CLL). Our aim was to evaluate the optimal cut-off for IgVh mutational status, ZAP-70 expression and cytogenetic abnormalities in association with disease progression defined as the need for treatment within 3~years from diagnosis in 170 patients with B-CLL. DESIGN AND METHODS: Receiver operating characteristics (ROC) analysis and multivariate general linear models (GLMs) were used to investigate the most significant cut-off values of these biomarkers and their prognostic impact. RESULTS: Our findings estimated that the optimal cut-off for IgVh mutation status and for ZAP-70 protein expression was 97% and 16.5% respectively and a high concordance between the two was demonstrated. We identified 30% as being the best-cut-off for 17p-, 11q- and 6q-. In univariate analysis 17p- was found to be a significant predictor of the event only for the whole population. Multivariate analysis including all biological parameters, identified 11q deletion as the only significant regressor. CONCLUSIONS: We assessed that IgVh mutational status, ZAP-70 protein and 6q- are powerful prognostic markers. Analyses of all these factors revealed that 11q deletion was the strongest predictor of disease progression in B-CLL.

Molecular analysis of PDGFRA and PDGFRB genes by rapid single-strand conformation polymorphism (SSCP) in patients with core-binding factor leukaemias with KIT or FLT3 mutation.

BACKGROUND: Mutations involving KIT and FLT3 genes, encoding tyrosine kinase (TK) membrane receptors, are detected in core-binding factor leukaemia (CBFL) patients. PDFGRA and PDGFRB encode class III TK receptors and are involved both in physiological processes and in the pathogenesis of haematological and solid tumours. The aim of this study was to investigate if PDGFR mutations are involved in CBFL. PATIENTS AND METHODS: In order to detect PDGFR mutations in CBFL, 35 patients without KIT or FLT3 mutations patients were screened by rapid and sensitive single-strand conformation polymorphism (SSCP) analysis. Sequence analysis was performed in polymerase chain reaction (PCR) products showing altered mobility in SSCP analysis in order to determine the nucleotide changes. RESULTS: Three types of single-nucleotide polymorphism (SNP) were detected in the PDGFRA gene (exon 12, exon 13 and exon 18) while no mutation of PDGFRB was detected in the tested CBFLs. CONCLUSION: These data showed that no pathogenic mutations in PDGFRA and PDGFRB were detected in the context of CBFL without KIT and FLT3 mutations. Thus, PDGFR genes do not seem to be involved in CBFL and future studies are needed to establish the genetic causes of the disease in these particular patients.