Autologous peripheral blood stem cell mobilization and apheresis in pediatric patients with cancer: A single-center report of 64 procedures.

BACKGROUND: The published experience concerning autologous peripheral blood stem cell collection in children is very limited. METHODS: The data of pediatric patients who underwent autologous stem cell mobilization and apheresis between January 2011 and April 2020 were analyzed retrospectively. RESULTS: We studied retrospectively 64 mobilization and apheresis procedures in 48 pediatric patients (34 males, 14 females), mean age of 7.31 ± 5.38 (range, 1.5-19.7) years, the underlying disease was mostly neuroblastoma (NBL). The body weight of 21 patients (43.75%) was 15 kg or less. The targeted autologous peripheral stem cell apheresis (APSCA) was successfully achieved in 98% of patients. Neuroblastoma patients were younger than the rest of the patients and underwent apheresis after receiving fewer chemotherapy cycles than others and all of them mobilized within the first session successfully. Plerixafor was added to mobilization in nine heavily pretreated patients (18.7%), median two doses (range, 1-4 doses). 11 patients (22.9%) underwent radiotherapy (RT) before mobilization with doses of median 24 Gy (range, 10.8-54.0 Gy). Patients with RT were older at the time of apheresis and had received more chemotherapy courses than patients without RT. As a result, patients with a history of RT had significantly lower peripheral CD34+ cells and CD34+ yields than those without RT. In 17 patients (35.4%), 22 different complications were noted. The most common complications were catheter-related infections (n:10, 20.8%), followed by catheter-related thrombosis in eight patients (16.7%). CONCLUSIONS: Patients who had far less therapy before apheresis were more likely to mobilize successfully. Our study provides a detailed practice approach including complications during APSCA aiming to increase the success rates of apheresis in transplantation centers.

Comparative evaluation of fluoride-free remineralization agents with and without Er,Cr:YSGG laser on artificial enamel remineralization.

This study aimed to evaluate the efficacy of fluoride-free remineralizing agents in initial enamel caries, with and without combined Er,Cr:YSGG laser application. The remineralization effect of various agents and their combinations on artificial initial caries was investigated using 10 experimental groups (n = 7): NC, negative control; PC, positive control; TM, calcium-phosphate compounds (CPP-ACP); TD, theobromine-containing toothpaste; RG, ROCS® remineralizing gel; L, Er,Cr:YSGG laser (2780 nm; 0.25 W; repetition rate, 20 Hz; pulse duration, 140 µs; tip diameter, 600 µm; without air/water cooling); L + fluoride toothpaste; L + TM; L + TD; and L + RG. The demineralized bovine enamel specimens were subjected to an 8-day pH cycle by daily application of the remineralizing agents and laser therapy once prior to the pH cycle and paste application. The enamel samples underwent the Vickers surface microhardness test, and one sample per group was analyzed with scanning electron microscopy. The Kruskal Wallis test was used to compare the microhardness recovery percentage (SMHR%) for each group, and multiple comparisons were made with the Dunn test. Groups L (p = 0.003), RG (p = 0.019), L + TM (p < 0.001), L + fluoride toothpaste (p = 0.001),and L + RG (p = 0.036) exhibited significant increase in SMHR%. The tested remineralizing agents exhibited no statistically significant difference in effect when used alone and in combination with Er,Cr:YSGG laser. Combined application of Er,Cr:YSGG laser and ROCS® remineralization gel effectively promoted enamel remineralization, while use of CPP-ACP and fluoride toothpaste alone was ineffective. Theobromine-containing toothpaste exhibited the least SMHR%. Long-term evaluation of these agents is recommended.

Pyruvate kinase deficiency mimicking congenital dyserythropoietic anemia type I.

BACKGROUND: Pyruvate kinase (PK) deficiency is the most common enzyme abnormality in the glycolytic pathway. Here, we describe two siblings with PK deficiency that mimicked congenital dyserythropoietic anemia (CDA) type I. CASE: The siblings were referred to our hospital for evaluation of anemia when they were newborns. Their PK enzyme activities were normal. Their bone marrow aspirations and electron microscopies showed CDA-like findings. A CDA panel with next-generation sequencing showed no mutation. Though their PK enzyme levels were normal, a molecular study of the PKLR gene showed a homozygous variant c.1623G > C (p.Lys541Asn) in exon 12 of our patients. CONCLUSIONS: Although the diagnosis of pyruvate kinase deficiency is difficult, it can be confused with many other diagnoses. Bone marrow findings of these cases are similar to congenital dyserythropoietic anemia. In patients with normal pyruvate kinase enzyme levels, the diagnosis cannot be excluded and genetic analysis is required.

The Mutation of CD27 Deficiency Presented With Familial Hodgkin Lymphoma and a Review of the Literature.

This study aimed to report 4 siblings with CD27 deficiency presented with Hodgkin lymphoma. The father of the family, his 2 wives, and 17 children born from these wives were included into the study. CD27 mutation of all the family members with, and without Hodgkin lymphoma were studied. The variants detected by the exome sequencing analysis were verified by Sanger sequencing and analyzed using SeqScape Software 3. It was determined that both the father of the family and his 2 wives carried the same variant heterozygously. Of the children born to the first mother, 2 children were normal, 3 were heterozygous and 5 were homozygous. Four of these 5 homozygous children were diagnosed with Hodgkin lymphoma. Of the children born to the second mother, 1 child was normal, 3 children were heterozygous and 2 children were homozygous, and none of them had developed a malignant event. We also showed that CD27 deficiency may enhance Treg differentiation. According to our information, this study augmented the relationship of Hodgkin lymphoma and CD27 deficiency. The detection of homozygous CD27 variant in all siblings who developed lymphoma strengthened the place of this mutation in the etiology of Hodgkin lymphoma. In contrast, the presence of homozygous siblings with no malignant event suggested the possible contributions of environmental factors on the etiology.

Clinical Profile and Outcomes of Primary Immunodeficiency and Malignancy in Childhood at a Tertiary Oncology Center in Developing Country.

Primary immune deficiencies are a group of heterogenous genetic disorders characterized by frequent infections, autoimmunity and malignancy. In this study, we aimed to evaluate clinical characteristics, outcomes of children with malignancy developed on background of primary immunodeficiency and compare survival rates of patients between malignant lymphoma with primary immunodeficiency and without immunodeficiency from tertiary oncology center in a developing country. A total 23 patients with primary immunodeficiency and malignancy were evaluated retrospectively. A total of 26 malignancies (first or second) in 23 patients were determined. The median age at the time of the first malignancy was 8 years (ranges 2-18 years) with increased male ratio (M/F:14/9). Non-Hodgkin lymphoma (n = 17; 65%) was the most common malignancy, followed by Hodgkin lymphoma (n = 5), anaplastic ependymoma (n = 1), spinal glioblastoma multiforme (n = 1), retinoblastoma (n = 1) and intracranial hemangiopericytoma (n = 1). The median follow-up time of patients was 25 months (ranges between 1 and 189 months). The 5-year overall survival rate of patients with malignant lymphoma associated with primary immunodeficiency (41%) were lower than immunocompetent patients with malignant lymphoma (80%) (p = 0.000). The 5-year overall survival of patients was diagnosed between 2021 and 2013 years (62%) was higher than previous years (22%) (p = 0.03). In conclusion, non-Hodgkin lymphomas were the most common histopathologic type in patients with malignancy associated with primary immunodeficiency in the present study. The survival of patients with malignant lymphoma associated with primary immunodeficiency has improved in recent years, yet it is still lower than immunocompetent patients with lymphoma and new targeted drugs are required for better survival rates.

Clinical and Demographic Characteristics of Cutaneous Mastocytosis in Childhood: Single-center Experience.

INTRODUCTION: Mastocytosis is a rare and heterogenous disease, and in children it is generally limited to the skin and tends to regress spontaneously in adolescence. AIM: In this study, demographic, clinical, and laboratory characteristics of pediatric patients with mastocytosis, and also coexisting diseases were investigated. RESULTS: A total of 61 pediatric patients were included in the study. The male-to-female ratio was 2.2, the median age was 2 years (range, 0.25 to 19 y), and the median follow-up period was 2.0 years (range, 0.25 to 19 y). Types of clinical presentation at diagnosis consisted of mainly urticaria pigmentosa (45.9%). Seven patients were further investigated with suspicion of systemic mastocytosis, they were followed up, median of 9 years (range, 2.5 to 16 y), and none of them developed systemic disease. Coexisting allergic diseases were recorded in total 5 patients (8.2%). Three patients had immunoglobulin A deficiency, 1 patient had elevated immunoglobulin E level. A patient developed mature B-cell lymphoma with a heterozygous mutation in c-KIT exon 11. DISCUSSION: Cutaneous mastocytosis in children may present as a complex disease with different clinical signs and symptoms. Standardized clinical criteria and guidelines for the follow-up of children with mastocytosis are required.

Hepatitis-Associated Aplastic Anemia: Etiology, Clinical Characteristics and Outcome.

Hepatitis-associated aplastic anemia (HAA) is a form of acquired aplastic anemia (AA) in which bone marrow failure develops after an acute attack of hepatitis. Bone marrow failure leading to AA is generally severe in cases of HAA and fatal if left untreated. This retrospective multicenter study investigated clinical and laboratory characteristics, possible causes, treatment, and outcome of HAA in children. Twenty patients from 8 centers were included in the study. Aspartate aminotransferase and alanine aminotransferase were <3 to 5×upper limit of normal (ULN) in 2 patients, <5 to 10×ULN in 2 patients, and >10×ULN in 16 patients. Acute liver failure developed in 5 (29%) patients. Pancytopenia was simultaneously present in 6 of 20 (30%) patients. Eleven of the 20 patients (55%) were alive, in remission and transfusion free. Those who were alive either had undergone hematopoietic stem cell transplantation and/or immunosuppressive treatment, except 1 patient who had received no treatment. Patients with the diagnosis of acute hepatitis should be evaluated and followed up carefully for presence of cytopenia, so that definitive treatment of AA can be initiated in a timely and appropriate manner when needed.

Cancer and constitutional Mismatch Repair Deficiency syndrome due to homozygous MSH 6 mutation in children with Café au Lait Spots and review of literature.

BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare childhood cancer predisposition syndrome resulting from biallelic germline mutations of mismatch repair (MMR) genes. CMMRD syndrome is characterised by early onset malignancies in children. CASE: Here we present affected children of consanguinous parents diagnosed with CMMRD syndrome due to germline bi-allelic MSH 6 gene mutations with café au lait spots and multiple family cancers from Turkey and reported cases with CMMRD syndrome associated MSH 6 mutation in English literature. Hence, we reviewed English literature from 1990 to 2020 using Pub-Med database. Keywords used to search included constitutional mismatch repair deficiency syndrome, childhood cancer and MSH 6 gene mutation. CONCLUSIONS: We emphasize that the inclusion of CMMRD syndrome in the differential diagnosis of a patient who presents with cafe´ au lait spots and/or hypopigmented skin lesions and cancer especially when consanguinity and/or a history of cancer coexist in children.

Successful treatment of multiple relapsed-refractory Langerhans cell histiocytosis with cyclosporine.

Langerhans cell histiocytosis is a rare hematologic disorder and patients who fail first-line treatment have a poor prognosis, and require more intensive treatment. We present an infant diagnosed with multisystem Langerhans cell histiocytosis refractory to multimodal therapy who was successfully treated with cyclosporine. Cyclosporine might be an effective alternative drug as nonmyelosuppressive rescue therapy for multiple relapsed-refractory Langerhans cell histiocytosis that has not achieved remission with cladribine and cytarabine therapy.

Thrombolysis with Systemic Recombinant Tissue Plasminogen Activator in Children: A Multicenter Retrospective Study

Objective: This study aimed to evaluate systemic thrombolysis experiences with recombinant tissue plasminogen activator (rtPA). Materials and Methods: Retrospective data were collected from 13 Turkish pediatric hematology centers. The dose and duration of rtPA treatment, concomitant anticoagulant treatment, complete clot resolution (CCR), partial clot resolution (PCR), and bleeding complications were evaluated. Low-dose (LD) rtPA treatment was defined as 0.01-0.06 mg/kg/h and high-dose (HD) rtPA as 0.1-0.5 mg/kg/h. Results: Between 2005 and 2019, 55 thrombotic episodes of 54 pediatric patients with a median age of 5 years (range: 1 day to 17.75 years) were evaluated. These patients had intracardiac thrombosis (n=16), deep vein thrombosis (DVT) (n=15), non-stroke arterial thrombosis (n=14), pulmonary thromboembolism (PE) (n=6), and stroke (n=4). The duration from thrombus detection to rtPA initiation was a median of 12 h (range: 2-504 h) and it was significantly longer in cases of DVT and PE compared to stroke, non-stroke arterial thrombosis, and intracardiac thrombosis (p=0.024). In 63.6% of the episodes, heparin was initiated before rtPA treatment. LD and HD rtPA were administered in 22 and 33 of the episodes, respectively. Concomitant anticoagulation was used in 90% and 36% of the episodes with LD and HD rtPA, respectively (p=0.0001). Median total duration of LD and HD rtPA infusions was 30 h (range: 2-120 h) and 18 h (2-120 h), respectively (p=0.044). Non-fatal major and minor bleeding rates were 12.5% and 16.7% for LD and 3.2% and 25.8% for HD rtPA, respectively. At the end of the rtPA infusions, CCR and PCR were achieved in 32.7% and 49.0% of the episodes, respectively. The most successful site for thrombolysis was intracardiac thrombosis. HD versus LD rtPA administration was not correlated with CCR/PCR or bleeding (p>0.05). Conclusion: Systemic thrombolytic therapy may save lives and organs effectively if it is used at the right indications and the right times in children with high-risk thrombosis by experienced hematologists with close monitoring of recanalization and bleeding.

Ovarian Mucinous Carcinoma in a Pediatric Patient With Maroteaux-Lamy Syndrome.

Mucopolysaccharidoses (MPS) are autosomal recessive lysosomal storage disorder (LSD). Mucinous ovarian cancer is a rare tumor and seldom encounters among adolescents. Here we describe an adolescent female with MPS type VI diagnosed with mucinous ovarian cancer. To our knowledge, this is the first case report of ovarian mucinous carcinoma in a patient with MPS. The association between MPS and cancer has never been described so far, but some LSD are known to have an increased risk of malignancies. The pathogenetic link between LSD and cancer is not well understood. Several potential mechanisms have been proposed for pathogenesis, which include chronic inflammation, abnormal function of activated macrophages, and genetic modifiers. Further studies are required, to understand the role of LSD in cancer.

A case of infective endocarditis due to Herbaspirillum Huttiense in a pediatric oncology patient.

Infective endocarditis (IE) is an infection of the endocardium and/or heart valves that involves thrombus formation (vegetation). This condition might damage the endocardial tissue and/or valves. An indwelling central venous catheter is a major risk factor for bacteremia at-risked pediatric populations such as premature infants; children with cancer and/or connective tissue disorders. Herbaspirillum huttiense is a Gram-negative opportunistic bacillus that may cause bacteremia and pneumonia rarely in this fragile population. Herein we report the very first case of bacteremia and IE in a pediatric oncology patient caused by H. huttiense.

Bioactivity evaluation of calcium silicate-based endodontic materials used for apexification.

This study aims to compare the bioactivity of Biodentine, ProRoot MTA and NeoMTA Plus with regard to their element uptake (Ca, Si and Ca/P) by root canal dentine in a simulated apex (n = 30 each) and evaluate the correlation between the dentine fracture resistance (n = 30 each) and interfacial layer thickness. Specimens immersed in a corrected simulated body solution (c-SBF) for 1, 30 and 90 days were used. In all test materials, the Ca and Si concentrations in the root dentine were found to be significantly higher, whereas the Ca/P and Si concentrations increased over time (P < 0.05). The dentine fracture resistance showed a difference at only day 30. The dentine fracture resistance of Biodentine and ProRoot MTA was positively correlated with the Si and Ca/P values, and the mean interfacial layer thickness of all specimens. A high biomineralisation capacity of ProRoot MTA and Biodentine, and their positive effects on the dentine fracture resistance during the first 30 days suggest that they may present more advantages than NeoMTA Plus in apexification treatment.

Evaluation of Final-Year Turkish Dental Students' Knowledge, Attitude, and Self-Perceived Competency towards Preventive Dentistry.

BACKGROUND: Dental education plays an important role in providing students with the opportunity to develop their evidence-based knowledge and clinical skills regarding patient-specific preventive care and caries management strategies. The aims of this study were to examine the knowledge, attitude, and self-perceived competency towards preventive dentistry among final-year dental students and to investigate their preventive practice for high-caries-risk children. Methods. Data were collected from a convenience sample of 126 dental students using a questionnaire. The IBM SPSS Statistics version 21 was used for data analysis. RESULTS: A total of 126 students completed the questionnaire, and 63% of the respondents were female. Significant gender differences were found in the total Professional Preventive Knowledge Scale (PPKS) (p=0.016) and its subscales of the noncariogenic nutrition (p=0.015), dental hygiene/clinical examination (p < 0.001), caries-preventive practice (p=0.02), and the Hiroshima University-Dental Behavioral Inventory (HU-DBI) (p=0.028). Significant differences were observed in the total PPKS (p=0.003) and its subscales of the noncariogenic nutrition (p=0.043) and caries risk management (p=0.006) in terms of self-perceived need to receive education and training. Caries-preventive practice was correlated with the self-perceived competency (r = 0.279; p=0.002), the attitudes (r = 0.394; p < 0.001), the total PPKS (r = 0.457; p < 0.001) and its all subscales of dental hygiene and clinical examination (r = 0.425; p < 0.001), noncariogenic nutrition (r = 0.410; p < 0.001), and caries risk management (r = 0.184; p=0.039). The self-perceived competency was positively correlated with the total PPKS (r = 0.192; p=0.031) and its subscale of noncariogenic nutrition (r = 0.259; p=0.003). Greater self-perceived competence, more positive attitudes, and good knowledge regarding preventive dentistry were found to be important predictors of the caries-preventive practice of dental students, explaining 31% of the variance (adjusted R 2 = 0.312, p < 0.001). CONCLUSION: 40% of dental students reported educational and training needs regarding the diagnosis, caries-preventive agents, and risk-based treatment plan. These results should be taken into account by the stakeholders in developing the national core curriculum for undergraduate Turkish dental education.

Evaluation of Crossbites in Relation with Dental Arch Widths, Occlusion Type, Nutritive and Non-nutritive Sucking Habits and Respiratory Factors in the Early Mixed Dentition.

PURPOSE: The purpose of this study was to analyse the connection between dental arch widths, malocclusion type, nutritive sucking habits and non-nutritive sucking habits, and respiratory factors with the presence of crossbites (CB) in the early mixed dentition. MATERIALS AND METHODS: Data were collected from 72 children with and without CB. A questionnaire was applied to parents/carers to obtain information about nutritive and non-nutritive sucking habits. The posterior and anterior crossbites were diagnosed in a centric relationship. Dental arch widths were measured directly from the models by two calibrated examiners. The data were analysed statistically using chi-square and Fisher's exact tests. RESULTS: The incidence of Class III malocclusion and the presence of ear, nose and throat problems in the study group were significantly higher than in the control subjects (p = 0.01, p = 0.047). The mean breastfeeding duration for children in the CB group was found significantly shorter than in the control subjects (p = 0.043). The number of children with mouth breathing in sleep was significantly higher in the CB group than the control subjects (p = 0.046). The children with CB demonstrated a statistically significant increase in mandibular intercanine width (ICW) than the control group (p = 0.044). CONCLUSION: The results demonstrated that an insufficient duration of breastfeeding, mouth breathing, ear-nose-throat problems and Class III malocclusion were associated with the presence of CB in the early mixed dentition.

Management of acquired aplastic anemia in children : A single center experience.

Acquired aplastic anemia (AAA) is a rare and potentially life threatening disorder. We retrospectively compared the outcomes of 29 children with AAA who received immunosuppressive therapy (IST) or underwent hematopoietic stem cell transplantation (HSCT). Median age at diagnosis was 9.0 years (range, 2-18 years) and median follow-up period was 36 months (range, 3-108 months). Viral infection associated/post hepatitis AAA was in 6 patients (20.6%). According to the initial laboratory findings, 8 patients were classified as very severe AA (vSAA), 8 as severe AA (SAA), and 13 patients as transfusion-dependent moderate AA (MAA). Out of 13, 5 transfusion-dependent MAA patients progressed SAA in median one month (range, 1-5 months), another 6 MAA patients developed remission or became transfusion free during follow-up. Eight patients underwent upfront matched family donor (MFD) HSCT at median 6 months (range, 1-9 months) and achieved complete response (100%). Fifteen cycles of IST were given to 10 (34%) patients lacking MFD at median 3 months (range, 2-6 months). Fifty percent of patients had complete/partial response after IST protocol. Three patients who were unresponsive to IST, proceeded to alternative donor HSCT, in 2nd or 3rd year after the diagnosis and only 1 patient was sustained remission. Several drugs such as mycophenolatemofetil, high-dose cyclophosphamide, levamisole and eltrombopag have been investigated in order to improve the outcome of patients with AAA. Early intervention in AAA patients results in significantly better outcomes.

Oral microbial dysbiosis in patients with Kostmann syndrome.

PURPOSE: The oral microbiome is maintained by host- and microbe-derived factors. A shift in microbial composition, as a result of diseases related to the immune system, is the most important step in the development of oral and dental diseases. The aim of this study was to investigate the oral microbial composition of patients with Kostmann syndrome, who have severe neutropenia, compared with healthy children. METHODOLOGY: A group of nine Kostmann syndrome patients and a group of nine healthy controls participated. After clinical investigation, DNA from stimulated saliva specimens was examined by high-throughput sequencing of the V3-V4 hypervariable region of the 16S rRNA gene using Illumina sequencing. The QIIME software package was used for 16 S rRNA amplicon analysis, while the Greengenes database was used for taxonomic classification. RESULTS: The periodontal pocket depths, plaque indices and bleeding-on-probing percentages and caries status on the deciduous teeth of the patients with Kostmann syndrome were statistically higher than those for the healthy controls. Patients with Kostmann syndrome had significantly lower bacterial diversity as compared to the controls. The presence of Firmicutes was statistically higher in patients with Kostmann syndrome, while that for Proteobacteria was higher in samples from the healthy controls (P<0.05). Streptococcus, Rothia, Granulicatella, Actinomyces, and genera from the family Gemellaceae were present as the core microbiome (abundance >1 % in at least 75  % of samples) in all groups, whereas the genus Porphyromonas was only detected as a member of the core microbiome in Kostmann patients. CONCLUSIONS: The evidence of lower bacterial diversity and differences in microbial profile for patients with Kostmann syndrome not only shows the impact of immune system-related diseases on oral microbiota, but also endorses the ecological plaque hypothesis proposed for the aetiology of oral diseases such as dental caries and periodontitis.

Refugee children with beta-thalassemia in Turkey: Overview of demographic, socioeconomic, and medical characteristics.

AIM: Since the beginning of the Syrian civil war, more than 3.5 million Syrians have been under temporary protection status in Turkey. Because beta-thalassemia (BT) is a prevalent disorder in the Mediterranean countries, we decided to estimate the prevalence of and make an overview of the demographic, socioeconomic, medical characteristics, and healthcare problems of refugee children with BT. PATIENTS: Eighteen Turkish Pediatric Hematology Oncology Centers (PHOC) with 318 refugee children from 235 families participated in the study. The mean age of the patients was 8.1 ± 4.8 years (0.5-21 years). The mean time after immigration to Turkey was 2.5 ± 1.5 years (range, 0.1-7 years). Seventy-two (22.6%) of them were born and diagnosed with BT in Turkey. On physical examination, 82 patients (26%) were underweight and 121 patients (38%) were stunted. The appearance of a thalassemic face was reported for 207 patients (65.1%). Hepatomegaly and splenomegaly were reported in 217 (68.2%) and 168 (52.8%) patients, respectively. The median ferritin level was 2508 ng/mL (range, 17-21 000 ng/mL) at the first admission, and 2841 ng/mL (range, 26-12 981 ng/mL) at the last visit after two years of follow-up in a PHOC (P > 0.05). The most frequently encountered mutation was IVSI-110 (G>A) (31%). Before immigration, only 177 patients (55.6%) reported the use of chelators; after immigration it increased to 268 (84.3%). CONCLUSION: Difficulties in communication, finding a competent translator capable in medical terminology, nonregular use of medications, and insensitivity to prenatal diagnosis were preliminary problems. The current extent of migration poses emerging socioeconomic and humanitarian challenges for refugee patients with BT.

Do PD-1 and PD-L2 expressions have prognostic impact in hematologic malignancies?

Background/aim: PD-1 (programmed death-1) is an immune checkpoint receptor that modulates T-cell activity in peripheral tissues via interaction with its ligands, PD-L1 (programmed death-ligand 1) and PD-L2 (programmed death-ligand 2). Tumor cells upregulate PD-L1 or PD-L2 to inhibit this T lymphocyte attack. Our goal was to determine the PD-1 and PD-L2 expression rates of various hematologic malignancies, and evaluate whether PD-1 and PD-L2 expressions have an impact on prognosis. Materials and methods: For this purpose, pretreatment bone marrow biopsy specimens of 83 patients [42 multiple myeloma (MM), 21 acute leukemia, and 20 chronic lymphocytic leukemia (CLL)] were stained with monoclonal antibody immunostains of PD-1 and PD-L2. Results: As a result, the overall expression rate of PD-1 was 26.2%, 4.8%, and 60% in patients with MM, acute leukemia, and CLL, respectively, whereas the PD-L2 expression rate was 61.9%, 14.3%, and 10% in patients with MM, acute leukemia, and CLL, respectively. Conclusion: Finally, we concluded that the role of the PD-1 pathway can be demonstrated by immunohistochemistry (IHC). Since we evaluated whether there is a correlation between the (IHC) results and survival of patients with MM, acute leukemia, and CLL, we could not demonstrate meaningful evidence that these markers have an impact on prognosis.