Differences in PD-1 expression on CD8+ T-cells in chronic myeloid leukemia patients according to disease phase and TKI medication

Malignant cells can increase in number using immune escape mechanisms such as immune checkpoints. In this study, we evaluated the expression of an immune checkpoint programmed death 1 (PD-1) on T-cell subsets in chronic myeloid leukemia (CML). We obtained bone marrow aspirate samples from CML patients and from individuals without evidence of hematologic malignancies (controls). PD-1 expression on T-cell subsets was measured using flow cytometric analysis. PD-1 expression levels on CD8+ T-cells were significantly lower in complete hematologic response (CHR) than in controls, chronic phase, and blast phase (BP). In CML patients receiving imatinib and dasatinib, PD-1 expression levels on CD8+ T-cells were lower than that at diagnosis. PD-1 expression levels on CD8+ T-cells were positively correlated with quantitative levels of the BCR/ABL fusion gene. PD-1 expression levels on CD4+ T-cells were higher in BP than in CHR. PD-1 expression levels on CD4+ T-cells did not differ significantly according to different medications or quantitative BCR/ABL1 fusion gene levels. Low PD-1 expression on CD8+ T-cells might play a role in maintaining CHR in CML patients. Immune monitoring of PD-1 expression on CD8+ T-cells may predict the disease course. In cases of refractory disease or resistance to imatinib or dasatinib, the use of PD-1 inhibitors would be helpful.

Increased expression of immune checkpoint programmed cell death protein-1 (PD-1) on T cell subsets of bone marrow aspirates in patients with B-Lymphoblastic leukemia, especially in relapse and at diagnosis

BACKGROUND

We analyzed expression profiles of immune checkpoint receptors on T cell subsets and ligands on leukemic blasts in patients with B-lymphoblastic leukemia (B-ALL).

METHODS

Total 149 bone marrow (BM) samples obtained from 65 B-ALL patients with four different clinical status (41 at diagnosis, 54 in complete remission [CR], 34 in persistence, and 20 in relapse), and 32 BM control samples were prospectively enrolled. Expression of immune checkpoint receptor (programmed cell death protein-1 [PD-1]) on T cell subsets and ligands (PD-L1, PD-L2) on leukemic blasts was evaluated by flow cytometry, and was compared between patient subgroups.

RESULTS

Relapsed patients demonstrated highest PD-1 expression proportion and intensity on CD3⁺ CD4⁺ T cells with statistical significance when compared to patients in persistence/CR/BM controls (p = .027/<.001/<.001 and .012/.001/<.001, respectively). Newly diagnosed patients showed significantly lower PD-1 expression proportion on CD3⁺ CD4⁺ T cells than relapsed patients (p < .001), but their intensity was not significantly different. Relapsed patients showed significantly higher PD-1 expression proportion and intensity on CD3⁺ CD8⁺ T cells than patients in CR/BM controls (p = .022/.045 and .049/.005, respectively), but PD-1 expression status on them were not significantly different between relapsed and newly diagnosed patients. PD-L1/L2 expression on leukemic blasts was not significantly different between patient subgroups.

CONCLUSIONS

In BM aspirates from B-ALL patients, PD-1 expression on T-cell subsets is increased at diagnosis, and to a greater extent, at relapse. These data suggest the potential usefulness of PD-1 blockade in the treatment of B-ALL, particularly at relapse.

Expression of Immune Checkpoint Receptors on T-Cells and Their Ligands on Leukemia Blasts in Childhood Acute Leukemia

BACKGROUND

Possible correlations between the expression of immune checkpoint molecules and prognosis in childhood acute leukemia were investigated.

MATERIALS AND METHODS

The expression of programmed-death 1 (PD1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and B- and T-lymphocyte attenuator (BTLA) was determined by flow cytometry on peripheral αβ⁺ and γδ⁺ T-cells from patients with newly diagnosed acute lymphoblastic leukemia (ALL) (n=9) or acute myeloid leukemia (AML) (n=12), and from healthy volunteers (n=7). The expression of programmed-death ligand 1 (PD-L1), B7-1, B7-2, human leukocyte antigen-ABC (HLA-ABC), and herpesvirus-entry mediator (HVEM) ligands was determined on leukemia blasts.

RESULTS

PD1 expression on αβ⁺ and γδ⁺ T-cells was significantly higher in patients with ALL than in those with AML (p=0.0019 and 0.0239, respectively). CTLA-4 expression was moderately higher on αβ⁺ and γδ⁺ T-cells in ALL (p=0.077 and 0.077, respectively), whereas HLA-ABC expression was significantly higher in AML blast cells (p=0.0182). The expression of CTLA-4 on γδ⁺ T-cells and the B7-2 ligand on blasts was higher in patients with high-risk ALL (p=0.02 and 0.02, respectively). In AML, PD1 expression on αβ⁺ T-cells was higher in the intermediate-risk group (p=0.05), whereas HVEM expression was significantly higher in the low-risk group (p=0.02). Expression of CTLA-4 on γδ+ T-cells and PD-L1 on blasts were both associated with poor relapse-free survival outcomes in ALL (p=0.049).

CONCLUSION

The higher expression of immune checkpoint molecules, in particular, CTLA-4 and PD-L1 are associated with a poorer prognosis in ALL, suggesting that selective use of the immune checkpoint blockade might improve the clinical outcomes in patients with ALL.

Abstract P3-03-31: Is sentinel lymph node biopsy necessary in all patients with early breast cancer?

Background and objectives : Since the results of the American College of Surgeons Oncology Group Z0011 published, the criteria for applying axillary lymph node (ALN) dissection was relaxed among early breast cancer patients who were scheduled for breast conserving surgery, adjuvant chemotherapy therapy, and adjuvant radiation therapy. SLNB criteria may be established if pathologic nodal status can be predicted. The aim of this study was to develop a nomogram for preoperative prediction of axillary node metastasis.

Methods: The records of 1650 patients with T1, T2 primary invasive breast cancer who were treated between January 2013 and September 2016 were selected from the medical database of Yonsei University (Seoul, South Korea). Those whom a preoperative diagnosis of axillary node metastases were excluded. Two nomogram that predicted three or more axillary metastasis and one or more axillary metastasis were developed using a binary logistic regression model with a training cohort. Internal validation was carried out adopting bootstrap method by validation cohort 500 times resampling.

Result: A total of 82 (4.8%) patients had three or more ALNs metastasis. Three hundred seventy five (17.4%) patients had one or more ALNs metastasis. Axillary metastasis was associated with Preoperative ALN suspicious image findings, clinical tumor size, Number of neoplastic foci, estrogen receptor status, Ki-67 expression, tumor marker. The nomogram was developed based on the clinical and statistically significant predictors. It had good discrimination performance (AUC 0.79, 95% CI, 0.73–0.85), (AUC 0.71, 95% CI, 0.67–0.74) and calibration fit.

Conclusion:Our nomogram might help predict the ALN metastasis in breast cancer patients. Patients with a low probability of ALN metastasis could be spared SLNB.

Citation Format: Yoon KH, Lee KB, Lee H, Lee J, Kim JY, Park HS, Park S, Kim SI, Cho YU, Park B-W. Is sentinel lymph node biopsy necessary in all patients with early breast cancer? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-31.

Abstract OT2-01-03: A prospective pilot study of simultaneous robotic assisted nipple sparing mastectomy and immediate reconstruction

Endoscopic breast surgery was expected to be an adequate technique to complete cancer clearance and preservation of the patient's body image. However, this technique has limitations including incomplete internal movements and unstable vision of a two dimensional camera due to inflexible endoscopic instruments especially during the skin flap formation. High resolution, ten-fold image magnification, and three-dimensional optics of robotic surgery help overcome the limitations of endoscopic surgery, and thus robotic surgery has been adopted in a wide range of intracorporeal procedures including breast surgery. However, few studies have evaluated feasibility and safety of robotic assisted nipple sparing mastectomy (RANSM) and immediate breast reconstruction (IBR) for the treatment of breast cancer. There were not any investigation to assess patients' satisfaction of cosmetic effect after performing RANSM and IBR. This study is aim to verify the feasibility and the safety of RANSM and IBR and to analyze cosmetic effect of the procedure and satisfaction of patients. The target number of enrollments is 15 patients. Patients who are diagnosed with early breast cancer or BRCA 1/2 mutation carriers are enrolled. Female patients over 20 years old who are candidates to preserve nipple areolar complex and considered to perform reconstruction with implants are prospectively collected. Written informed consents are mandatory. Patients who are considered the high possibility of postoperative radiation therapy according to preoperative stage are not included in this study. We exclude patients who want to undergo other methods of breast reconstruction than breast reconstruction with implants. Patients will undergo RANSM and IBR through a single axillary skin incision simultaneously. Regular follow-up at 1 month and 6 months after RANSM and IBR is scheduled to record recovery of a patient, amount of a drain, date of drain removal, and postoperative complications. Patient satisfaction questionnaire will be completed on the last follow-up day. To evaluate the safety of robotic assisted surgery, the oncologic safety (margin status of nipple areolar complex), postoperative recovery of a patient, and postoperative complications are investigated. We compare preoperative and postoperative 6 month photographs of patients and estimate the surgical outcome by objective indicators to evaluate the cosmetic grading by plastic surgeons. Patients' satisfaction are assessed by questionnaire (BREAST-Q) at the 6-month visit.

Citation Format: Lee J, Park HS, Kim JH, Lee DW, Song SY, Lew DH, Kim JY, Kim SI, Cho YU, Lee H, Lee KB, Yoon KH. A prospective pilot study of simultaneous robotic assisted nipple sparing mastectomy and immediate reconstruction [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-01-03.

Morulae in neutrophils: A diagnostic clue for human granulocytic anaplasmosis

Although there was no specific finding in peripheral blood smears performed on the second day after doxycycline administration in clinically suspected human granulocytic anaplasmosis (HGA) patients, we re-examed the peripheral blood smears performed at the time of admission and found morulaes in neutrophils. This case shows that the detection of morulae in a blood smear can be helpful in the diagnosis of HGA, especially in the acute phase of illness, prior to empirical antibiotic administration.

Comparable Outcome with a Faster Engraftment of Optimized Haploidentical Hematopoietic Stem Cell Transplantation Compared with Transplantations from Other Donor Types in Pediatric Acquired Aplastic Anemia

Haploidentical family donors have been used as an alternative source in hematopoietic cell transplantation for patients with severe aplastic anemia. We evaluated and compared the outcomes of transplantation in pediatric acquired severe aplastic anemia based on donor type. Sixty-seven patients who underwent transplantation between 1998 and 2017 were included. Fourteen patients received grafts from matched sibling donors, 21 from suitable unrelated donors, and 32 from haploidentical family donors. Ex vivo CD3⁺ or αβ⁺ T cell-depleted grafts were used for haploidentical transplantation. Sixty-five patients (97.0%) achieved neutrophil engraftment at a median of 11 days. Haploidentical transplantation resulted in significantly faster neutrophil engraftment at a median of 10 days, compared with 14 days in cases of matched sibling donors and 12 days in cases of unrelated donor recipients. Nine patients experienced graft failure, and 5 of 7 who underwent a second transplantation are alive. There was no difference in the incidence of acute or chronic graft-versus-host disease based on donor type. The 5-year overall survival and failure-free survival rates were 93.8% ± 3.0% and 83.3% ± 4.6%, respectively, and there was no significant survival difference based on donor type. The survival outcomes of haploidentical transplantation in patients were comparable with those of matched sibling or unrelated donor transplantation. Optimized haploidentical transplantation using selective T cell depletion and conditioning regimens including low-dose total body irradiation for enhancing engraftment may be a realistic therapeutic option for pediatric patients with severe aplastic anemia.

Blast Percentage of Bone Marrow Aspirate on Day 14 of Induction Chemotherapy Predicts Adult Acute Lymphoblastic Leukemia Treatment Outcomes

The prognosis of adult acute lymphoblastic leukemia is much worse than that of pediatric acute lymphoblastic leukemia, even when patients achieve complete remission. Early response to treatment can be an important alternative indicator of treatment outcomes. The purpose of our current study was to identify the prognostic value of the blast percentage of the induction interim bone marrow, which might predict relapse-free survival and overall survival in patients with adult acute lymphoblastic leukemia. A retrospective analysis was performed on 80 adult patients diagnosed with Philadelphia chromosome-negative acute lymphoblastic leukemia from 1994 to 2011. Complete remission was observed in 75 (93.8%) patients after induction chemotherapy. On multivariate analysis, a reduction of blasts to a level of 5% or less in the induction interim bone marrow and CD20 positivity were significant prognostic predictors of relapse-free survival (hazard ratio, HR = 2.88, p = 0.006, and HR = 2.67, p = 0.010) and overall survival (HR = 2.10, p = 0.033, and HR = 2.39, p = 0.013). The blast percentage of the induction interim bone marrow may be a useful prognostic factor to predict outcome.

Abstract OT2-01-03: A prospective randomized study comparing surgery using electrosurgical bipolar sealing devices and surgery using conventional electro-cautery

Background: Seroma and lymphorrhea are the most common complication following mastectomy and/or axillary lymph node dissection (ALND). The manifestation of seroma accelerates complications such as post-operative bleeding, wound infection, prolonged recovery period. Sealing blood vessels and lymph drainages adequately during mastectomy and/or ALND may play a main role in reducing complication. Therefore, adequate sealing vessels and lymphatics during the surgery is important to reduce seroma and lymphorrhea related complications in patients with breast cancer. Objective: This study aims to show that electrosurgical bipolar sealing device for mastectomy could provide clinical benefit in reducing seroma formation. Design: ELBCE (ELectrosurgical Bipolar Devices VS Convention Electronicautery, NCT03166384)is a prospective, randomized, two-arm assignment controlled trial of application of electrosurgical bipolar sealing device for mastectomy in patients with breast cancer. Patients is randomized in 1:1 ratio to conventional suture and tie group or electrosurgical bipolar sealing devices group. Randomization is performed using opening sealed envelope before enrollment. The primary end point is to compare the total drainage volume until drain tube removal. The time to drain removal is also measured. The secondary end points is the total amount of aspiration from seroma after drain tube removal, and the frequency of seroma aspiration. Statistical consideration: A sample size 44 subjects per each arm was planned to provide a 90% power to detect a 25% decrease of the total amount of drainage fluid after surgery by using an electrosurgical bipolar sealing device when compared to a conventional suture and tie technique. In our experience, the average total volume of fluid after conventional suture and tie technique is 220 mL, with a standard deviation of 80. Eligibility criteria:Inclusion criteria are patients older than 20 years and those who planned to undergo total mastectomy and/or ALND. Exclusion criteria are bilateral breast cancer patients, male patients, patients who underwent ipsilateral axillar surgery or radiation therapy, recurrent breast cancer patients, patients without drain catheter, and patients with ductal carcinoma in situ who have not undergone ipsilateral sentinel lymph node biopsy or ALND.Present accrual and target accrual:ELSEBA study has an accrual target of 88 patients. To date, 8 patients have been randomized. Contact information:Dr. Hyung Seek Park, E-mail: hyungseokpark.md@gmail.com; imgenius@yuhs.ac, Telephone: +82-2-2228-2100

Citation Format: Yoon KH, Park HS, Kim JH, Kim JY, Lim SM, Kim SI, Cho YU. A prospective randomized study comparing surgery using electrosurgical bipolar sealing devices and surgery using conventional electro-cautery [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-01-03.

Abstract P6-11-13: Not presented

This abstract was not presented at the symposium.

Clinical Isolation of Anaplasma phagocytophilum in South Korea

We report the first isolation of Anaplasma phagocytophilum in South Korea. A 61-year-old woman presented with a 6-day history of fever, headache, and myalgia. Initial investigation showed neutropenia and thrombocytopenia. We diagnosed human granulocytic anaplasmosis by microscopic examination and serologic testing. The patient recovered fully without antibiotic therapy. The isolate was obtained from the patient's blood by cell culture and mouse inoculation. Its identity was confirmed by an immunofluorescence assay, sequencing of the 16S rRNA gene, msp2 (p44), and ankA genes, and staining and electron microscopy of morulae of A. phagocytophilum in cultured human promyelocytic leukemia HL-60 cells.

Frequency and Clinicopathologic Features of RUNX1 Mutations in Patients With Acute Myeloid Leukemia Not Otherwise Specified

OBJECTIVES

To evaluate the frequency and clinicopathologic characteristics of RUNX1 mutations, focusing on patients with acute myeloid leukemia not otherwise specified (AML NOS).

METHODS

Diagnostic samples from 219 patients with AML NOS were analyzed for RUNX1 mutations using standard polymerase chain reaction and direct sequencing.

RESULTS

Thirty-one RUNX1 mutations were detected in 33 (15.1%) patients. Mutations clustered in the Runt homology (61.3%) and transactivation domains (25.8%). Frameshift mutations were most common (51.6%), followed by missense (41.9%) and nonsense (6.5%) mutations. Patients with RUNX1 mutations had a lower platelet count (P = .013) and shorter relapse-free survival (P = .045) than those without. The presence of RUNX1 and NPM1 or CEBPA mutations was mutually exclusive. A literature review, including our study, showed that patients with RUNX1 mutations were associated with intermediate risk; coexisting mutations such as FLT3-ITD, ASXL1, TET2, and DNMT3A; and a relatively cytogenetic heterogeneity.

CONCLUSIONS

Our findings strengthen previous data concerning RUNX1 mutations in AML and support the notion that RUNX1 mutational status should be integrated into a diagnostic workup of AML, particularly for AML NOS or an intermediate-risk group.

Prognostic significance of recurrent additional chromosomal abnormalities in adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

In Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL), additional chromosomal abnormalities (ACAs) are frequently observed. We investigated the cytogenetic characteristics and prognostic significance of ACAs in Ph-positive ALL. We reviewed the clinical data and bone marrow cytogenetic findings of 122 adult Ph-positive ALL patients. The ACAs were examined for partial or whole chromosomal gains or losses, and structural aberrations. The overall survival (OS) and disease-free survival (DFS) of patients who received hematopoietic cell transplantation were compared between the isolated Ph group and ACA group. ACAs were present in 73.0% of all patients. The recurrent ACAs were extra Ph (24.7%), 9/9p loss (20.2%), and 7/7p loss (19.1%). Complex karyotype was found in 28.1% of patients in the ACA group. Younger patients (19-30 years) in the ACA group showed the highest frequency of extra Ph (54%) compared to other age groups. The OS in the ACA group was significantly shorter than in the isolated Ph group. The presence of an extra Ph chromosome or 9/9p loss was significantly associated with shorter OS and DFS, whereas 7/7p loss and complex karyotype were not associated with poorer prognosis. We suggest that subclassification of ACAs could be applied to prognostic investigation of Ph-positive ALL.

Multidisciplinary Approach to Decrease In-Hospital Delay for Stroke Thrombolysis

Background and Purpose

Decreasing the time delay for thrombolysis, including intravenous thrombolysis (IVT) with tissue plasminogen activator and intra-arterial thrombectomy (IAT), is critical for decreasing the morbidity and mortality of patients experiencing acute stroke. We aimed to decrease the in-hospital delay for both IVT and IAT through a multidisciplinary approach that is feasible 24 h/day.

Methods

We implemented the Stroke Alert Team (SAT) on May 2, 2016, which introduced hospital-initiated ambulance prenotification and reorganized in-hospital processes. We compared the patient characteristics, time for each step of the evaluation and thrombolysis, thrombolysis rate, and post-thrombolysis intracranial hemorrhage from January 2014 to August 2016.

Results

A total of 245 patients received thrombolysis (198 before SAT; 47 after SAT). The median door-to-CT, door-to-MRI, and door-to-laboratory times decreased to 13 min, 37.5 min, and 8 min, respectively, after SAT implementation (P<0.001). The median door-to-IVT time decreased from 46 min (interquartile range [IQR] 36–57 min) to 20.5 min (IQR 15.8–32.5 min; P<0.001). The median door-to-IAT time decreased from 156 min (IQR 124.5–212.5 min) to 86.5 min (IQR 67.5–102.3 min; P<0.001). The thrombolysis rate increased from 9.8% (198/2,012) to 15.8% (47/297; P=0.002), and the post-thrombolysis radiological intracranial hemorrhage rate decreased from 12.6% (25/198) to 2.1% (1/47; P=0.035).

Conclusions

SAT significantly decreased the in-hospital delay for thrombolysis, increased thrombolysis rate, and decreased post-thrombolysis intracranial hemorrhage. Time benefits of SAT were observed for both IVT and IAT and during office hours and after-hours.

Role of Horizontal Transfer of the Transposon Tn1546in the Nosocomial Spread ofvanAVancomycin-Resistant Enterococci at a Tertiary Care Hospital in Korea

Objective:

To investigate the epidemiologic characteristics of vancomycin-resistant enterococci (VRE) infection.

Design.

An epidemiologic description by means of chromosomal DNA fingerprinting and transposon typing.

Setting.

A 2,200-bed tertiary care hospital in Korea.

Patients.

First VRE isolates were obtained from patients hospitalized from April 1997 to December 2001.

Interventions.

Thevangenotypes of isolates were identified by means of multiplex polymerase chain reaction (PCR). The macro-restriction patterns of chromosomal DNA were determined by pulsed-field gel electrophoresis (PFGE). The transposon Tn1546was typed by means of 2 sets of long PCR restriction fragment-length polymorphism analysis, which wereClaI restriction of a 10.4-kb region fromorf1tovanZandDdeI restriction of a 4.4-kb region fromvanRtovanX.

Results.

VRE isolates were recovered from 215 patients. All werevanAgenotype. PFGE analysis of the 215 isolates showed 172 types, including 21 clusters composed of 64 isolates and 151 types of as many isolates. Each type was composed of 2-10 isolates; the isolates within each PFGE cluster were detected within a 10-month period and mostly shared a transposon type. Transposon typing classified 169 strains into 15 types and 158 strains belonged to 4 major transposon clusters. Each of these 4 transposon clusters was isolated from patients treated in 5-22 different wards during a 31-52 month period and consisted of 9-80 PFGE types. Each of the other 11 types were found in only one strain.

Conclusions.

Our findings suggest that the horizontal transfer of Tn1546has a major role in the nosocomial spread ofvanAVRE. Clonal spread of VRE seemed to contribute to short-term dissemination in limited areas.

Immunophenotypic markers in adult acute lymphoblastic leukemia: the prognostic significance of CD20 and TdT expression

BACKGROUND

Efforts to overcome poor outcomes in patients with adult acute lymphoblastic leukemia (ALL) have focused on combining new therapeutic agents targeting immunophenotypic markers (IPMs) with classical cytotoxic agents; therefore, it is important to evaluate the clinical significance of IPMs.

METHODS

Baseline characteristics and clinical outcomes of patients with adult ALL were retrospectively analyzed. The percentage of blasts expressing IPMs at diagnosis was measured by multicolor flow cytometry analysis. Samples in which ≥20% of blasts expressed an IPM were considered positive.

RESULTS

Among the total patient population (N=230), almost all (92%) were in first or second hematological complete remission (HCR) and 54% received allogeneic hematopoietic cell transplant (allo-HCT). Five-year hematologic relapse-free survival (HRFS) and overall survival (OS) rates were 36% and 39%, respectively, and 45.6% and 80.5% of patients were positive for the IPMs CD20 and terminal deoxynucleotidyl transferase (TdT), respectively. Expression of CD20, CD13, CD34, and TdT was associated with HRFS rate, and expression of CD20 and CD13 was associated with OS rate, as was the performance of allo-HCT. In multivariate analysis, positivity for CD20 (HRFS: hazard ratio [HR], 2.21, P<0.001; OS: HR, 1.63, P=0.015) and negativity for TdT (HRFS: HR, 2.30, P=0.001) were both significantly associated with outcomes. When patients were categorized into three subgroups according to positivity for CD20 and TdT, there were significant differences in HRFS and OS among the subgroups.

CONCLUSION

Positivity for CD20 and TdT expression and clinical risk group were prognostic factors in adult ALL.

MRP1 and P-glycoprotein expression assays would be useful in the additional detection of treatment non-responders in CML patients without ABL1 mutation

We evaluated the ability of the rhodamine-123 efflux assay, multidrug resistance-associated protein-1 (MRP1) expression assay and P-glycoprotein (Pgp) expression assay to discriminate chronic myelogenous leukemia (CML) patients who had failed treatment or were at risk of failure. Each assay was performed in blood samples from CML patients (n=224) treated with tyrosine kinase inhibitors, taken at diagnosis (n=14) and follow-up (n=210). Patient samples were categorized as optimal response (n=120), suboptimal response (n=54), and treatment failure (n=36). Treatment-failed patients had a significantly higher MRP1 expression (5.24% vs. 3.54%, P=0.006) and Pgp expression (5.25% vs. 3.48%, P=0.005) than responders. Both MRP1 (%) and Pgp (%) were highly specific (95.2% and 94.5%) and relatively accurate (83.0% and 82.5%) in the detection of treatment non-responders. Of treatment-failed patients, 41.2% had a positive result in at least one assay and of these patients without ABL1 kinase domain mutation, 51.9% were positive in at least one assay. However, the rhodamine-123 efflux assay failed to discriminate two patient groups. Thus, both MRP1 and Pgp expression assays could be useful for additional identification of treatment non-responders in CML patients without ABL1 mutation.

JAK2 V617F, MPL, and CALR Mutations in Korean Patients with Essential Thrombocythemia and Primary Myelofibrosis

Mutations in the calreticulin gene, CALR, have recently been discovered in subsets of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). We investigated Korean patients with ET and PMF to determine the prevalence, and clinical and laboratory correlations of CALR/JAK2/MPL mutations. Among 84 ET patients, CALR mutations were detected in 23 (27.4%) and were associated with higher platelet counts (P=0.006) and lower leukocyte counts (P=0.035) than the JAK2 V617F mutation. Among 50 PMF patients, CALR mutations were detected in 11 (22.0%) and were also associated with higher platelet counts (P=0.035) and trended to a lower rate of cytogenetic abnormalities (P=0.059) than the JAK2 V617F mutation. By multivariate analysis, triple-negative status was associated with shorter overall survival (HR, 7.0; 95% CI, 1.6-31.1, P=0.01) and leukemia-free survival (HR, 6.3; 95% CI, 1.8-22.0, P=0.004) in patients with PMF. The type 1 mutation was the most common (61.1%) type among all patients with CALR mutations, and tended toward statistical predominance in PMF patients. All 3 mutations were mutually exclusive and were never detected in patients with other myeloid neoplasms showing thrombocytosis. CALR mutations characterize a distinct group of Korean ET and PMF patients. Triple-negative PMF patients in particular have an unfavorable prognosis, which supports the idea that triple-negative PMF is a molecularly high-risk disease.