Preferentially Expressed Antigen Of Melanoma Gene Expression Research Articles

Correlation of preferentially expressed antigen of melanoma (PRAME) gene expression with clinical characteristics in acute leukemia patients

BackgroundPreferentially expressed antigen of melanoma (PRAME) gene is regularly overexpressed in acute leukemia (AL) and other malignant diseases which are recognized by human leucocyte antigen (HLA-24) located in the human chromosome of 22q11 coded by 509 amino acids. To rule out the PRAME gene expression in AL patients and its correlation with clinical characteristics in the Indian population set up by RT-qPCR. ResultsA total of 42 samples collected, 29 (69.4%) were males, and 13 (30.95%) were females, with a mean and standard deviation for age were 39.07 ± 22.22 years. Of which AML were of 22 (52.38%) cases, ALL were of 14 (33.33%) cases, and 6 (14.2%) cases which included other forms of leukemia. PRAME gene expression was highly expressed in thirty-three 27 (64.28%) AL patients compared to the least expression in healthy individuals. No significant difference between the different forms of AL (p=0.3203) was observed. Cytogenetic analysis of normal karyotype (NK), abnormal karyotype (Ab. K), and culture failure (CF) displayed statistical non-significance (p=0.5801). Among cytogenetic abnormalities obtained, no significant differences between the groups were observed (p=0.8507). Chloride, potassium, and absolute lymphocyte count (ALC) was found to be statistically significant with p=0.0038**, p=0.0358*, and p=0.0216*, respectively, between all other clinical characteristics. There was no correlation between the PRAME gene expression and clinical parameters. ConclusionPRAME gene expression in AL patients was highly expressed, comparable to studies reported globally with significant cytogenetic results. PRAME gene could be used as a potential diagnostic marker for monitoring the malignancies and minimal residual disease in AL.

Clinical Importance of PRAME Gene Expression in Acute Myeloid Leukemia

Background: The PRAME (preferentially expressed antigen of melanoma) gene is frequently over expressed in a wide variety of malignant diseases, including acute myeloid leukemia (AML). Objective: To investigate the expression of PRAME gene in AML and its importance in the prognosis. Patients and methodsThe transcript level of PRAME gene was detected in peripheral blood specimens from 72 de novo AML patients and 40 control subjects by using real-time quantitative PCR and the prognostic value of PRAME was determined through treatment outcome and survival analysis. Results: PRAME gene was highly expressed in 74% of de novo AML cases while low expression was detected among healthy controls, the mean value of PRAME gene expression was highest among M3 AML subtype and lowest among M5b AML subtype. No significant correlation could be observed between PRAME gene expression and different CBC parameters, age, gender or cytogenetics, but there was a significance positive correlation between PRAME gene expression with treatment outcome, disease free survival (DFS) and overall survival. Conclusion: PRAME gene over expression might be a good prognostic factor of AML and could be a useful target for immunotherapy.

Prognostic Significance of WT1 and PRAME Gene Expression in Bone Marrow Samples of MDS and AML Patients Treated with Azacytidine

Introduction: The Wilms’ tumor gene (WT1) and preferentially expressed antigen of melanoma (PRAME) gene are frequently overexpressed in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) Combined quantitation of PRAME and WT1 transcript levels could provide a powerful molecular marker in newly diagnosed MDS patients, enabling the early identification of relapse through minimal residual disease monitoring and also to enable alternate treatment strategies (Qin et al, 2012).In this study, we investigated the prognostic impact of WT1 and PRAME gene expression on MDS and AML patients treated with azacytidine.Methods:In this ethically approved, retrospective study, we studied WT1 and PRAME gene expression in the bone marrow of 20 patients with MDS and AML (unsuitable for more intensive chemotherapy) prior to starting epigenetic therapy with azacytidine (100mg/M2 sc for 5 days every 28 days). 20 patients with lymphoma not involving the bone marrow were used as a control group. Quantitative assessment of WT1 and PRAME transcript levels was performed on formalin fixed paraffin-embedded trephine biopsies, using the WT1 Ipsogen ProfileQuant and a ‘homebrew’ kit respectively. A control GADPH was used. Overall survival was extimated using the Kaplan-Meier method and compared using the log-rank test. The logistic regression model was used to correlate IPSS-R with WT-1 and PRAME gene expression levels.Results: The median age of the patient group was 71. 16 patients had MDS (RCMD: 3; RARS: 2; RAEB1: 2; RAEB2: 5; CMML: 4) and 4 had AML. Median age of the control group was 61. Median number of cycles of azacytidine was 4 (range 1-21). In 11 of the patient group and in all of the controls, neither PRAME nor WT1 gene expression was detected.. PRAME gene expression without WT1 gene expression was detected in 5 patients, whilst, in the remaining 4 patients, both PRAME and WT1 gene expression was detected. There was no significant difference in mean percentage of bone marrow blasts between patients with detectable PRAME +/- WT1 gene expression (16.67%) and those without (12.64%).Median gene expression levels of PRAME +/- WT1 significantly correlated with IPSS-R (p=0.003).Overall survival (OS) was significantly inferior in patients who were positive for PRAME +/- WT1 (p=0.0103). Median OS for patients positive for both PRAME and WT1 was 270 days and for patients who were PRAME positive and WT1 negative was 300 days, whilst patients negative for both had a median OS of 630 days (figure 1).Conclusions: Our study results show that patients who have detectable WT1 and PRAME expression in their bone marrow prior to azacytidine therapy have more advanced disease in terms of IPSS-R score and have a much inferior OS compared to patients without detectable WT1 and PRAME. Such patients should be considered for either additional or alternate therapy to single agent azacytidine. DisclosuresNo relevant conflicts of interest to declare.

PRAME Gene Expression in Childhood Acute Lymphoblastic Leukemia: Impact on Prognosis

The PRAME (preferentially expressed antigen of melanoma) gene is frequently overexpressed in a wide variety of malignant diseases, including acute myeloid leukemia (AML) and acute B-cell malignancies. To study the expression of PRAME gene and clarify its prognostic impact on disease outcome. Screening for PRAME gene expression was assessed using real-time reverse transcriptase polymerase chain reaction in 55 pretreated ALL bone marrow samples. PRAME positivity was found in 14 (31.3%) of 45 patients. No significant correlation could be observed between PRAME expression and clinical characteristics. Positive PRAME expressers had a statistically higher CR (p = 0.001), lower relapse (p = 0.02), lower mortality (p < 0.001), a trend towards lower Refractory disease (p = 0.10), and a statistically longer DFS and OS (p < 0.001, < 0.001, respectively) in comparison to negative PRAME expressers. Our results suggested that PRAME was a predictor for better outcome, could be a useful target for immunotherapy, and might represent a candidate marker for the monitoring of minimal residual disease.

Correlation between Preferentially Expressed Antigen of Melanoma and Tumour Necrosis Factor-Related Apoptosis-Inducing Ligand Gene Expression in Different Types of Leukaemia Patients

Introduction: Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) down-regulation by preferentially expressed antigen of melanoma (PRAME) is a general phenomenon in different types of solid tumours, but research on the correlation between PRAME and TRAIL gene expression in leukaemia patients is rare. Method: PRAME and TRAIL expression was detected in bone marrow samples from 80 newly diagnosed acute leukaemia (AL) patients and 40 chronic myeloid leukaemia (CML) patients using TaqMan-based real-time quantitative PCR methods, and a linear correlation analysis was performed on their levels of expression. A total of 15 normal bone marrow samples from individuals with non-malignant haematological diseases served as normal controls. Results: PRAME expression was higher in both AL and CML patients compared to controls (both p < 0.001). CML patients in both blast crisis (BC) and the accelerated phase (AP) had significantly higher PRAME levels than CML patients in the chronic phase (CP) (p = 0.006 and 0.0461, respectively). TRAIL expression was higher in both the acute myeloid leukaemia (AML) group and the acute lymphoblastic leukaemia (ALL) group than in the controls (p = 0.039 and 0.047, respectively). In contrast, CML patients had lower TRAIL levels than controls (p = 0.043), and TRAIL expression in CML patients in the advanced phases (BC and AP) was significantly lower than in CML-CP patients (p = 0.006). In CML patients, there was a significant inverse correlation (Spearman's R = -0.6669, p < 0.0001) between PRAME and TRAIL gene expression, while a greater significant inverse correlation was found in patients in the advanced phases (BC and AP) (R = -0.6764). In addition, no correlation was observed in AML and ALL patients. Conclusion: The simultaneous detection of PRAME and TRAIL gene expression may be helpful to monitor condition changes in leukaemia patients and evaluate therapeutic effects in clinical practice, particularly in CML patients.

PRAME Gene Expression in Acute Leukemia and Its Clinical Significance.

ObjectiveTo investigate the expression of the preferentially expressed antigen of melanoma (PRAME) gene in acute leukemia and its clinical significance.MethodsThe level of expressed PRAME mRNA in bone marrow mononuclear cells from 34 patients with acute leukemia (AL) and in 12 bone marrow samples from healthy volunteers was measured via RT-PCR. Correlation analyses between PRAME gene expression and the clinical characteristics (gender, age, white blood count, immunophenotype of leukemia, percentage of blast cells, and karyotype) of the patients were performed.ResultsThe PRAME gene was expressed in 38.2% of all 34 patients, in 40.7% of the patients with acute myelogenous leukemia (AML, n=27), and in 28.6% of the patients with acute lymphoblastic leukemia (ALL, n=7), but was not expressed in the healthy volunteers. The difference in the expression levels between AML and ALL patients was statistically significant. The rate of gene expression was 80% in M3, 33.3% in M2, and 28.6% in M5. Gene expression was also found to be correlated with CD15 and CD33 expression and abnormal karyotype, but not with age, gender, white blood count or percentage of blast cells.ConclusionsThe PRAME gene is highly expressed in acute leukemia and could be a useful marker to monitor minimal residual disease. This gene is also a candidate target for the immunotherapy of acute leukemia.

Effect of 5-Azacytidine (5-AzaC) In the Expression of PRAME In Acute Myeloid Leukemia (AML)

AbstractAbstract 3615 Introduction:Preferentially expressed antigen of melanoma (PRAME) was first isolated as a human melanoma antigen by cDNA expression cloning using melanoma-reactive cytotoxic Tcells (CTL). PRAME is a tumor associated antigen (TAA) of particular interest since it is widely expressed by lymphoid and myeloid malignancies and solid tumors. Several studies have associated high PRAME RNA levels with good prognosis in acute myeloid leukemia (AML). In addition, several authors have suggested that PRAME could be used as a target for anticancer T-cell therapy. PRAME expression is regulated at the epigenetic level. For this reason inhibitors of DNA methylation, such as 5-azacytidine, can modulate the expression of this TAAs. In the current study we analyzed the effect of 5-azaC on the expression of PRAME in blasts versus CD34+ cells from healthy donors in an attempt to increase its expression, thus inducing a potential target for therapeutic strategies. Methods:We analyzed PRAME mRNA expression of blast cells from AML patients at diagnosis versus CD34+ stem cells from healthy donors by RT-PCR without treatment or after exposure to 1mM 5-azaC during the four days of culture and correlated the expression of PRAME with the methylation status of the promoter. Results:PRAME is significantly over-expressed in blasts from AML patients (n=11) compared with normal CD34+ cells (n=8) ((700±1102 vs. 1.8±2.5 p=0.002). Interestingly, we found an inverse correlation between PRAME expression and the degree of methylation in the promoter among both AML samples and healthy donors (r=-0.77 p=0.010). In order to evaluate the effect of 5-azaC on PRAME gene expression, we treated blast cells and CD34+ cells from healthy donors with the drug and we observed that the exposure to the drug induced a decrease in the percentage of methylation in the promoter and subsequently increased the expression of PRAME but, interestingly, the higher the basal methylation of the promoter the more intense the effect of the drug among AML cells. By contrast, CD34+ cells from healthy donors were resistant to the effect of the drug so that no significant changes were observed neither in terms of methylation status of the promoter nor in the expression of PRAME prior to or after exposure to the drug among healthy donors. Conclusions:The promoter region is highly methylated in normal CD34+ cells compared to AML cells and this pattern correlates with a higher expression of PRAME in blasts. Furthermore, the level of PRAME methylation was reduced in AML patients after exposure to 5-azaC which correlated with an increase in the expression of PRAME. By contrast, the effect of 5-azaC on the methylation pattern of the promoter was significantly lower in CD34+ cells from healthy donors. Disclosures:Cañizo:Celgene: Membership on an entity's Board of Directors or advisory committees. San Miguel:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Jangssen-cilag: Membership on an entity's Board of Directors or advisory committees; millennium: Membership on an entity's Board of Directors or advisory committees. Off Label Use: The drug used in this study is the demethylating agent 5-azacytidine (5-azaC) and the purpose is to increase PRAME expression in blasts from AML patients and generate CTL CD8+ specific response against tumor cells.

Oncogene Associated cDNA Microarray Analysis Shows PRAME Gene Expression is a Marker for Response to Anthracycline Containing Chemotherapy in Patients with Diffuse Large B-cell Lymphoma

CHOP (cyclophosphamide, adriamycin, vincristine, and prednisolone) therapy achieves a response in more than 60% patients with diffuse large B-cell lymphomas (DLBCLs). However, DLBCL shows a heterogeneous response to chemotherapy, and some patients are refractory to CHOP therapy. This difference in response to therapy is most likely due to differences in biological characteristics. We used cDNA microarray analysis to identify genes differentially expressed in anthracycline containing chemotherapy-resistant DLBCLs (7 patients) compared with anthracycline containing chemotherapy-sensitive DLBCLs (6 patients). Nine genes on the cDNA chip showed increased expression in anthracycline containing chemotherapy-resistant patients. We chose the preferentially expressed antigen of melanoma (PRAME) gene because it showed the highest expression in anthracycline containing chemotherapy-resistant DLBCLs on the cDNA chip, and it has been linked to prognosis of hematological malignancies. We also examined the relationship between PRAME gene expression and progression-free survival (PFS) in 45 patients with DLBCL. The progression-free survival of PRAME-positive patients (n=12) was significantly worse than that of PRAME-negative patients (n=33) (p=0.0373). Our results therefore indicate that PRAME expression in DLBCL correlates with response to anthracycline containing chemotherapy.

PRAME expression and clinical outcome of breast cancer

The tumour antigen PReferentially expressed Antigen of MElanoma (PRAME) is expressed in a variety of malignancies, including breast cancer. We have analysed PRAME gene expression in relation to clinical outcome for 295 primary breast cancer patients. Kaplan–Meier survival curves show a correlation of PRAME expression levels with increased rates of distant metastases and decreased overall patient survival. This correlation existed both for the entire patient group (n=295) and for the subgroup of patients (n=185) who did not receive adjuvant chemotherapy. Multivariable analysis indicated that PRAME is an independent marker of shortened metastasis-free interval in patients who did not receive adjuvant chemotherapy. PRAME expression was associated with tumour grade and negative oestrogen receptor status. We conclude that PRAME expression is a prognostic marker for clinical outcome of breast cancer, independent of traditional clinicopathological markers.

Prevalence and prognostic and predictive relevance of PRAME in breast cancer

Preferentially expressed antigen of melanoma (PRAME) has been described as a potential candidate for immunotherapeutic targeting. However, the prognostic and predictive relevance of PRAME in breast cancer has never been investigated. PRAME gene expression was evaluated in 103 breast tumour biopsies, using quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Normal breast tissue was also analysed for comparative purposes. All qRT-PCRs were performed in triplicate. Kaplan-Meier survival curves, Chi-squared and Cox Regression analyses were used to identify associations between PRAME expression and patients' clinicopathological and survival data. PRAME mRNA was detected in approximately 53% of tumour specimens and 37% of normal breast specimens. Kaplan-Meier analysis showed expression of PRAME to correlate significantly with unfavourable disease outcome for patients, in terms of both their disease-free survival (p = 0.0004) and overall survival (OS) (p = 0.0052) times from diagnosis. Multivariate analysis indicated PRAME expression to be an independent prognostic factor for shortened disease-free survival (p = 0.026) and OS (p = 0.02). Furthermore, for patients who received adjuvant chemotherapy, significantly (p = 0.0291) shorter relapse-free survival was achieved for those whose tumour expressed PRAME, compared to those that did not express this transcript. Our results suggest that PRAME mRNA expression may be a useful prognostic and predictive marker for breast cancer.

Childhood acute myelogenous leukaemia: Association between PRAME, apoptosis- and MDR-related gene expression

The gene PRAME (preferentially expressed antigen of melanoma) encodes an antigen recognised by autologous cytolytic T lymphocytes. The mRNA level of PRAME is used as a tumour marker due to its overexpression in various malignancies. Furthermore, it is known that the overexpression of genes encoding antiapoptotic proteins leads to the survival of leukaemic cells via exclusion of apoptosis. On the other hand, overexpression of genes encoding ABC transporters may lead to multi drug resistance (MDR). Therefore, we investigated whether there is a relationship between PRAME overexpression and the expression of apoptosis- and MDR-related genes in childhood de novo acute myelogenous leukaemia (AML) patient samples and, furthermore, whether this is a general or an AML-subtype specific event. Microarray analysis and real time quantitative PCR revealed that clinical samples showing PRAME upregulation are associated with a decreasing expression of genes coding for apoptotic proteins and an overexpression of genes encoding ABC transporters. Our results indicate that patients showing PRAME upregulation may have an increased risk of MDR induction.

Real-time RT-PCR quantification of PRAME gene expression for monitoring minimal residual disease in acute myeloblastic leukaemia

Specific gene rearrangements are used for minimal residual disease (MRD) assessment, but are frequently lacking in leukaemias. In these cases, the quantification of PRAME (preferentially expressed antigen of melanoma) transcripts could be useful. PRAME transcripts were quantified by real-time RT-PCR in normal and leukaemic samples, and the results were compared with those of conventional RT-PCR. Basal expression of PRAME was determined in 25 blood samples and 25 bone marrow samples from healthy donors, as well as in 12 haematological cell lines (Jurkat, K562, HL60, DOHH2, IM9, Daudi, CEM, KG1, DG75, 8226, U937, Raji). In paediatric acute myeloid leukaemia (AML) (n=22) and acute lymphoblastic leukaemia (ALL) (n=17), and in adult AML (n=20), abnormal PRAME expression was found in 41%, 35% and 40% of cases, respectively. To assess the sensitivity of PRAME for monitoring MRD, PRAME-positive t(8;21) AML samples with detectable AML1/ETO expression by conventional RT-PCR (n=17) were assessed for quantitative expression of AML1/ETO and PRAME. The expression of these genes was closely correlated. To confirm that PRAME expression was correlated with clinical data, the expression of PRAME was also sequentially followed in patients (n=13) from onset to cytological remission or relapse. The cytological and molecular data were highly correlated in all patients. Our data confirm that PRAME quantification by real-time RT-PCR appears suitable for monitoring MRD in PRAME-positive leukaemia.

PRAME gene expression in childhood acute lymphoblastic leukemia

The gene PRAME (preferentially expressed antigen of melanoma) was found to be expressed at high levels in a large fraction of different tumors and adult leukemias. Since PRAME is only expressed at low levels in a few normal tissues and encodes an antigen recognized by autologous cytolytic T lymphocytes, it might be a good candidate for tumor immunotherapy. In this study, quantitative reverse transcriptase polymerase chain reaction was used to measure PRAME gene expression in 50 children with newly diagnosed acute lymphoblastic leukemia (ALL). Nine patients were also analyzed in relapse. Overexpression of PRAME was found in 42% ( N = 21) of the patients. In accordance with our findings in acute myeloblastic leukemia (AML) patients, the rate of disease-free survival was higher and white blood cell counts at diagnosis were lower in patients with an overexpression of PRAME. However, in our group of ALL patients these findings were not statistically significant. The levels of expression at diagnosis corresponded well with those at relapse ( P = 0.017). Although overexpression of PRAME was less frequent than in children with AML (62%) our results suggest that PRAME could be a useful target for immunotherapy in some children with ALL.