Acquired immune resistance is associated with interferon signature and modulation of KLF6/c-MYB transcription factors in myeloid leukemia.

Resistance to immunity is associated with the selection of cancer cells with superior capacities to survive inflammatory reactions. Here, we tailored an ex vivo immune selection model for acute myeloid leukemia (AML) and isolated the residual subpopulations as "immune-experienced" AML (ieAML) cells. We confirmed that upon surviving the immune reactions, the malignant blasts frequently decelerated proliferation, displayed features of myeloid differentiation and activation, and lost immunogenicity. Transcriptomic analyses revealed a limited number of commonly altered pathways and differentially expressed genes in all ieAML cells derived from distinct parental cell lines. Molecular signatures predominantly associated with interferon and inflammatory cytokine signaling were enriched in the AML cells resisting the T-cell-mediated immune reactions. Moreover, the expression and nuclear localization of the transcription factors c-MYB and KLF6 were noted as the putative markers for immune resistance and identified in subpopulations of AML blasts in the patients' bone marrow aspirates. The immune modulatory capacities of ieAML cells lasted for a restricted period when the immune selection pressure was omitted. In conclusion, myeloid leukemia cells harbor subpopulations that can adapt to the harsh conditions established by immune reactions, and a previous "immune experience" is marked with IFN signature and may pave the way for susceptibility to immune intervention therapies.

Precursor B-cell Lymphoblastic Lymphoma in Children: Hacettepe Experience.

The purpose of the study was to review the clinical and pathologic characteristics and treatment results of children with precursor B-cell lymphoblastic lymphoma. Of 530 children diagnosed with non-Hodgkin lymphomas between 2000 and 2021, 39 (7.4%) were identified as having precursor B-cell lymphoblastic lymphoma. Clinical characteristics, pathologic, radiologic, laboratory data, treatments, responses, and overall outcomes were recorded from hospital files and analyzed. The median age of 39 patients (males/females, 23/16) was 8.3 years (range 1.3 to 16.1). The most common sites of involvement were the lymph nodes. At a median follow-up of 55.8 months, 14 patients (35%) had a recurrence of disease (11 stage IV, 3 stage III); 4 were in complete remission with salvage therapies, 9 died of progressive disease and one died due to febrile neutropenia. Five-year event-free survival and overall survival rates were 65.4% and 78.3% for all cases, respectively. Survival rates were higher in patients with a complete remission at the end of induction therapies. The survival rates were lower in our study compared with other studies, which could be explained by the high relapse rate and higher incidence of advanced-stage disease due to bone marrow involvement. We demonstrated a prognostic impact of treatment response at the end of the induction phase. Cases with a disease relapse have poor prognosis.

Small cell lung cancer stem cells display mesenchymal properties and exploit immune checkpoint pathways in activated cytotoxic T lymphocytes.

Small cell lung cancer (SCLC) is an aggressive tumor type with early dissemination and distant metastasis capacity. Even though optimal chemotherapy responses are observed initially in many patients, therapy resistance is almost inevitable. Accordingly, SCLC has been regarded as an archetype for cancer stem cell (CSC) dynamics. To determine the immune-modulatory influence of CSC in SCLC, this study focused on the characterization of CD44+CD90+ CSC-like subpopulations in SCLC. These cells displayed mesenchymal properties, differentiated into different lineages and further contributed to CD8+ cytotoxic T lymphocytes (CTL) responses. The interaction between CD44+CD90+ CSC-like cells and T cells led to the upregulation of checkpoint molecules PD-1, CTLA-4, TIM-3, and LAG3. In the patient-derived lymph nodes, CD44+ SCLC metastases were also observed with T cells expressing PD-1, TIM-3, or LAG3. Proliferation and IFN-γ expression capacity of TIM-3 and LAG3 co-expressing CTLs are adversely affected over long-time co-culture with CD44+CD90+ CSC-like cells. Moreover, especially through IFN-γ secreted by the T cells, the CSC-like SCLC cells highly expressed PD-L1 and PD-L2. Upon a second encounter with immune-experienced, IFN-γ-stimulated CSC-like SCLC cells, both cytotoxic and proliferation capacities of T cells were hampered. In conclusion, our data provide evidence for the superior potential of the SCLC cells with stem-like and mesenchymal properties to gain immune regulatory capacities and cope with cytotoxic T cell responses. With their high metastatic and immune-modulatory assets, the CSC subpopulation in SCLC may serve as a preferential target for checkpoint blockade immunotherapy .

Adenosine Deaminase Type II Deficiency: Severe Chronic Neutropenia, Lymphoid Infiltration in Bone Marrow, and Inflammatory Features.

Deficiency of adenosine deaminase type 2 (DADA2) is an autoinflammatory disease characterized with immunologic, hematologic, and neurological features. Here, we presented two patients with severe persistent chronic neutropenia, which required differential diagnosis of congenital and autoimmune neutropenia, myelodysplastic syndrome (MDS), and primary immunodeficiency diseases, including autoimmune lymphoproliferative disease. The therapy of the disease except hematopoietic stem cell transplantation is a challenging experience.

Clonal B-cell proliferations developing in the background of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder: A case series.

Clonal B-cell proliferations and B-cell lymphomas may co-occur in the background of follicular helper T-cell (TFH)-derived lymphomas, most associated with EBV, which has been a well-known fact for many years in the prototypical entity "TFH lymphoma, angioimmunoblastic-type." Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (CD4+ PCSM-LPD) is also a TFH-derived clonal proliferation. We searched the archives and identified four cases of CD4+ PCSM-LPD with accompanying clonal B-cell proliferation (one of which showed EBER positivity), and one longstanding case of CD4+ PCSM-LPD, in the background of which a B-cell lymphoma had developed. These five cases broaden experience on CD4+ PCSM-LPD with accompanying B-cell proliferations and also support routine evaluation of these cases with EBV in situ hybridization, to better determine whether or not there is an association with EBV.

Diffuse Large B-Cell Lymphoma, Epstein-Barr Virus -Positive Kappa Monotypic Plasma Cell Proliferation and Invasive Carcinoma, Developing in a Child With Defective Mismatch Repair.

Constitutional mismatch repair deficiency (CMMRD) syndrome is characterized by biallelic mutations in a mismatch repair gene and is associated with development of childhood cancers and symptoms resembling neurofibromatosis type 1, like café-au-lait spots. We describe the extremely rare case of a 12-year-old male presenting with several light brown macular lesions on the skin, gastrointestinal diffuse large B-cell lymphoma, adenomatous polyposis throughout the gastrointestinal tract and an intra-abdominal invasive carcinoma derived from upper gastrointestinal system. All neoplasia, as well as normal tissues, showed loss of Msh6 expression with immunohistochemistry. Molecular studies showed pathogenic homozygous p.F1088Sfs*2 mutation in MSH6. Furthermore, signs consistent with immunodeficiency, namely decreased levels of IgG and IgA in the serum, nodular lymphoid hyperplasia and EBV-associated plasma cell proliferation with monotypic kappa light chain expression in the ileum, were also noted. Our case depicts the phenotypic diversity of CMMRD syndrome and emphasizes its association with immunodeficiency, raising awareness to a feature not widely recognized.

HER2-low breast cancer could be associated with an increased risk of brain metastasis.

PURPOSE: The HER2-low breast cancer is a newly recognized entity with the clinical characteristics is yet to be defined. We hypothesized that HER2-low breast cancer could lead to an increased rate of brain metastases in patients with localized breast cancer. We tested this hypothesis in a large cohort of breast cancer patients with long follow-up. METHODS: We included 2686 adult breast cancer patients followed up in Hacettepe University Cancer Center. Patients with 1 + positive HER2 expression and 2 + HER2 expression with a negative FISH were categorized as HER2-low disease. We evaluated the brain metastasis risk with binary logistic regression analyses and reported odds ratios (OR) with 95% confidence intervals (CI). RESULTS: During a median 95.4 (IQR 72.6-123.1) month follow-up, 184 patients developed brain metastasis (6.9%). The brain metastases were developed in 5.1% of the patients with HER2-negative disease, 8.5% of the patients with HER2-low disease, and 10.1% of the patients with HER2-positive disease. A multivariable binary logistic regression model demonstrated an increased risk of brain metastasis in patients with HER2-low disease (OR: 1.611, 95% CI 1.055-2.460, p = 0.027) and in HER2-positive patients (OR: 1.837, 95% CI 1.308-2.580, p < 0.001). Additionally, HR + -HER2-low disease was associated with a decreased DFS compared to HR + -HER2-negative disease (p = 0.008). CONCLUSION: In this study, we observed an increased risk of brain metastasis in localized breast cancer patients with HER2-low disease. We think that a high level of vigilance and a low threshold for brain imaging could benefit HER2-low breast cancer patients similar to the patients with HER-positive disease.

Genomic Spectrum and Phenotypic Heterogeneity of Human IL-21 Receptor Deficiency.

Biallelic inactivating mutations in IL21R causes a combined immunodeficiency that is often complicated by cryptosporidium infections. While eight IL-21R-deficient patients have been reported previously, the natural course, immune characteristics of disease, and response to hematopoietic stem cell transplantation (HSCT) remain to be comprehensively examined. In our study, we have collected clinical histories of 13 patients with IL-21R deficiency from eight families across seven centers worldwide, including five novel patients identified by exome or NGS panel sequencing. Eight unique mutations in IL21R were identified in these patients, including two novel mutations. Median age at disease onset was 2.5 years (0.5-7 years). The main clinical manifestations were recurrent bacterial (84.6%), fungal (46.2%), and viral (38.5%) infections; cryptosporidiosis-associated cholangitis (46.2%); and asthma (23.1%). Inflammatory skin diseases (15.3%) and recurrent anaphylaxis (7.9%) constitute novel phenotypes of this combined immunodeficiency. Most patients exhibited hypogammaglobulinemia and reduced proportions of memory B cells, circulating T follicular helper cells, MAIT cells and terminally differentiated NK cells. However, IgE levels were elevated in 50% of IL-21R-deficient patients. Overall survival following HSCT (6 patients, mean follow-up 1.8 year) was 33.3%, with pre-existing organ damage constituting a negative prognostic factor. Mortality of non-transplanted patients (n = 7) was 57.1%. Our detailed analysis of the largest cohort of IL-21R-deficient patients to date provides in-depth clinical, immunological and immunophenotypic features of these patients, thereby establishing critical non-redundant functions of IL-21/IL-21R signaling in lymphocyte differentiation, humoral immunity and host defense against infection, and mechanisms of disease pathogenesis due to IL-21R deficiency. Outcome following HSCT depends on prior chronic infections and organ damage, which should thus be considered as early as possible following molecular diagnosis.

Human splenic polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) are strategically located immune regulatory cells in cancer.

In contrast to the mouse, functional assets of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) in the human spleen remain to be better elucidated. Here, we report that the spleen in gastric and pancreatic cancer adopts an immune regulatory character, harbors excessive amount of PMN-MDSC, and anatomically enables their interaction with T cells. Compared to the peripheral blood, the spleen from cancer patients contained significantly higher levels of low-density PMN-MDSC, but not early-stage MDSC (e-MDSC) and monocytic-MDSC (M-MDSC). Low-density fraction of polymorphonuclear (PMN) cells was enriched in immature myeloid cells and displayed higher levels of CD10, CD16, and ROS than their blood-derived counterparts. They were also positive for PD-L1, LOX-1, and pSTAT3. The white pulp and periarteriolar lymphoid sheath (PALS) were strategically surrounded by PMN cells that were in contact with T cells. Unlike those from the blood, both low-density and normal-density PMN cells from the human spleen suppressed T cell proliferation and IFN-γ production. Independent of clinical grade, high PMN-MDSC percentages were associated with decreased survival in gastric cancer. In summary, our results outline the immune regulatory role of the spleen in cancer where neutrophils acquire MDSC functions and feasibly interact with T cells.

Tumor-Induced Myeloid Cells Are Reduced by Gemcitabine-Loaded PAMAM Dendrimers Decorated with Anti-Flt1 Antibody.

While reshaping their microenvironment, tumors are also capable of influencing systemic processes including myeloid cell production. Therefore, the tumor-induced myeloid cells, such as myeloid-derived suppressor cells (MDSCs), which are characterized with pro-cancer properties, became another target in order to increase the success of the therapy. This study evaluated the capacity of a novel dendrimeric drug delivery platform to eliminate tumor-induced myeloid cells. As described in a previous study by our research group, the anti-Flt1 antibody-conjugated polyethylene glycol (PEG)-cored poly(amidoamine) (PAMAM) dendrimers improved the efficacy of gemcitabine against pancreatic cancer. Here, the biodistribution studies showed that these dendrimeric structures accumulated in the compartments that became rich in myeloid cells in the pancreatic tumor-bearing mice. When gemcitabine was loaded into the dendrimer complexes, the number of myeloid cells was significantly reduced while the percentage distribution of granulocytic and monocytic myeloid cells was not always significantly altered. The CD11b+Ly6G-Ly6C+ monocytes were more severely affected by the treatments than CD11b+Ly6G+Ly6C+ granulocytes. Immune infiltration levels in the tumor tissue were also altered. Myeloid cells in the spleen and F4/80+ macrophages of the liver were protected. The compartments, such as the liver and the bone marrow, which are known to have high vascular endothelial growth factor (VEGF)-Flt1 pathway activity, were particularly targeted by gemcitabine when delivered through anti-Flt1 antibody-conjugated PAMAM dendrimers. In conclusion, chemotherapeutic agents complexed with dendrimers not only improve anticancer efficacy, but they also assist in the elimination of the tumor-induced myeloid cells.

Impact of repeated abdominal surgery on wound healing and myeloid cell dynamics.

BACKGROUND: Even though wound dehiscence is a surgical complication, under certain medical conditions, repetition of the laparotomy (LT) (relaparotomy) can become inevitable. In addition to the risks associated with this surgical operation, relaparotomy can interfere with the tissue healing and contribute to the development of chronic wounds. METHODS: In an experimental relaparotomy wounding model, this study investigated the impact of repeated surgery on wound healing and on the immune cells of myeloid origin. RESULTS: The first repeat of the LT triggered fibrosis and marginally interfered with the wound healing; however, the second operation completely abrogated the healing process. Splenomegaly was observed as an indicator of the chronic inflammation and the systemic effect of repeated laparotomies. In the blood stream, the spleen, and the liver, these repeated surgeries exhibited a major impact on the CD11b+Ly6C+Ly6G- monocytes. On the other hand, especially, whespecially the second relaparotomy resulted in a massive purging of neutrophil granulocytes into the circulation. These CD11b+Ly6C+Ly6G+ neutrophils that were disseminated on repeated abdominal laparotomies had a proinflammatory character that positively influenced T cell proliferation and displayed a high capacity for production of reactive oxygen species. CONCLUSIONS: The repetition of abdominal LT not only interferes with the wound healing but also contributes to the development of imperfectly healing wounds which have systemic impact on immune compartments.

Distribution of lymphomas in Turkey: data of 4239 cases from a single institution using the WHO classification

Background/aim: Lymphoma cases diagnosed at one of the largest tertiary reference centers in Turkey were reviewed and findings were compared to those reported from other regions of the world. Materials and methods: Lymphomas diagnosed between 2000 and 2017 in the pathology laboratory of Hacettepe University were identified. A total of 4239 cases were analyzed. The WHO 2008 classification was used. Results: Hodgkin lymphomas accounted for almost 20% of cases. T-cell lymphomas were much more frequent (23% of our non- Hodgkin lymphoma (NHL) cases) in comparison to all other regions of the world. The reason for this difference was the high frequency of mycosis fungoides (MF) cases. We had significantly more cases of high-grade B-cell lymphoma (43.9% of NHLs) and fewer cases of low-grade B-cell lymphoma (33.5% of NHLs) in comparison to the rates of developed regions of the world and the reverse was true when compared to developing parts of the world. Burkitt lymphoma frequency (4% of NHLs) was also higher than in most parts of the world. Conclusion: Our data reveal that the frequency of MF, Burkitt lymphoma, and Hodgkin lymphoma are considerably higher, whereas follicular lymphoma rates are considerably lower than in most other parts of the world.

Splenectomy-Induced Leukocytosis Promotes Intratumoral Accumulation of Myeloid-Derived Suppressor Cells, Angiogenesis and Metastasis.

BACKGROUND: Enlargement of the spleen is commonly observed in animal models of cancer. Here, in a breast cancer model, it was aimed to determine the effect of splenectomy on circulating and tumor-infiltrating myeloid-derived suppressor cells (MDSCs), tumor angiogenesis, and metastasis. METHODS: Mice were inoculated with 4T1 breast cancer cells and underwent splenectomy or sham laparotomy. Tumor growth and survival of animals were followed. Macroscopic and histopathological analyses were performed to determine splenomegaly and metastasis. Immunophenotyping of myeloid cells was performed with flow cytometric analysis of CD11b, Gr-1, F4/80, CD206, CD11c, and F4/80 markers. Suppressive function of MDSCs on T cell proliferation was studied in cocultures. Tumor angiogenesis and granulocytic myeloid cell infiltration in the metastatic foci were studied by CD31 and Ly6G immunohistochemistry, respectively. RESULTS: The mice bearing breast tumors underwent total splenectomy at an early time point of tumorigenesis when only low levels of MDSCs had accumulated in the spleen. Circulating and tumor-infiltrating MDSCs, and tumor-associated macrophages (TAMs) were increased following splenectomy. Nevertheless, splenectomy could only lead to a temporary deceleration in tumor growth but favored lung metastasis and angiogenesis in the long run. CONCLUSION: Our data demonstrated a link among splenectomy-induced leukocytosis, accumulation of circulating and tumor-infiltrating MDSC, and enhanced angiogenesis and metastasis. Therefore, as a part of oncological surgery, favorable and unfavorable facets of the splenectomy must be considered to improve therapeutic efficacy.

Chronic lymphocytic leukemia in a child: a challenging diagnosis in pediatric oncology practice.

Chronic lymphocytic leukemia/lymphoma (CLL) is an extremely rare disease during childhood. We report a 16-year-old female who presented with lymphadenopathies and she was diagnosed as T cell lymphoblastic lymphoma. Her chemotherapy response was minimal and clinical findings were unusual. Therefore, her biopsy specimen was re-examined and diagnosis was changed to CLL. Chemotherapy protocol including fludarabine, cyclophosphamide, rituximab was administrated and good response was observed. In our patient deletion at 1q21.2 region that includes aryl hydrocarbon receptor nuclear translocator (ARNT) gene was detected via comparative genomic hybridization method. ARNT gene deletion may be a new mutation in chronic lymphocytic leukemia development.

Nasal type natural killer T-cell lymphoma involving nasooropharynx and larynx.

Lymphoma is one of the malignant non-squamous tumors involving the head and neck. Lymphomas in this region are mostly B-cell type in origin and usually seen in Waldeyer's ring. In this article, we report a 45-year-old female case of primary natural killer T cell lymphoma-nasal type involving the nasooropharynx and larynx. This is a very rare entity with poor prognosis.

Myeloid sarcoma with RBM15::MRTFA (MKL1) mimicking vascular neoplasm.

Extramedullary involvement of acute myeloid leukemia (AML), aka myeloid sarcoma, is a rare phenomenon in acute megakaryoblastic leukemia with RBM15:: MRTFA(MKL1) fusion, which might mimic non-hematologic malignancies. A 7-month-old infant presented with leukocytosis, hepatosplenomegaly, multiple lymphadenopathies, and a solid mass in the right thigh. Initially, the patient was diagnosed with a malignant vascular tumor regarding the expression of vascular markers from the biopsy of the right thigh lesion that was performed after the inconclusive bone marrow biopsy. The second bone marrow biopsy, which was performed due to the partial response to sarcoma treatment, showed hypercellular bone marrow with CD34 and CD61-positive spindle cell infiltration and > 20% basophilic blasts with cytoplasmic blebs. RNA sequencing of soft tissue biopsy revealed the presence of RBM15::MRTFA(MKL1) fusion. Based on these findings, myeloid sarcoma/AML with RBM15::MRTFA(MKL1) fusion diagnosis was made. AML with RBM15::MRTFA(MKL1) fusion can initially present as extramedullary lesions and might cause misdiagnosis of non-hematologic malignancies.

Indolent B-cell non-Hodgkin lymphomas in children: high association with inborn errors of immunity.

Indolent lymphomas are rare in children and mostly consist of pediatric type follicular (PTFL) and pediatric marginal zone lymphomas (PMZL) and extranodal marginal zone lymphoma (ENMZL). Twenty children with indolent lymphoma (10 PTFL, 6 PMZL, 3 ENMZL, 1 mixed type) among 307 Non-Hodgkin Lymphoma (NHL) were retrospectively evaluated. The mean age of the entire group was 10.4 ± 4.4 and was significantly lower in PTFL than in PMZL. Seven patients (35%) had an associated inborn error of immunity (IEI) which was higher than that seen in aggressive lymphomas (5.9%) (p < 0.0001). Seventeen patients (85%) had stage I/II disease. Two patients received no treatment after surgery. Eleven patients were treated only with 3-6 courses of rituximab. Four patients received 3-6 courses of R-CHOP protocol. The prognosis was excellent Five years overall and event-free survivals were 100% and 85%, respectively.

Targeting TACC3 Induces Immunogenic Cell Death and Enhances T-DM1 Response in HER2-Positive Breast Cancer.

Trastuzumab emtansine (T-DM1) was the first and one of the most successful antibody-drug conjugates (ADC) approved for treating refractory HER2-positive breast cancer. Despite its initial clinical efficacy, resistance is unfortunately common, necessitating approaches to improve response. Here, we found that in sensitive cells, T-DM1 induced spindle assembly checkpoint (SAC)-dependent immunogenic cell death (ICD), an immune-priming form of cell death. The payload of T-DM1 mediated ICD by inducing eIF2α phosphorylation, surface exposure of calreticulin, ATP and HMGB1 release, and secretion of ICD-related cytokines, all of which were lost in resistance. Accordingly, ICD-related gene signatures in pretreatment samples correlated with clinical response to T-DM1-containing therapy, and increased infiltration of antitumor CD8+ T cells in posttreatment samples was correlated with better T-DM1 response. Transforming acidic coiled-coil containing 3 (TACC3) was overexpressed in T-DM1-resistant cells, and T-DM1 responsive patients had reduced TACC3 protein expression whereas nonresponders exhibited increased TACC3 expression during T-DM1 treatment. Notably, genetic or pharmacologic inhibition of TACC3 restored T-DM1-induced SAC activation and induction of ICD markers in vitro. Finally, TACC3 inhibition in vivo elicited ICD in a vaccination assay and potentiated the antitumor efficacy of T-DM1 by inducing dendritic cell maturation and enhancing intratumoral infiltration of cytotoxic T cells. Together, these results illustrate that ICD is a key mechanism of action of T-DM1 that is lost in resistance and that targeting TACC3 can restore T-DM1-mediated ICD and overcome resistance. SIGNIFICANCE: Loss of induction of immunogenic cell death in response to T-DM1 leads to resistance that can be overcome by targeting TACC3, providing an attractive strategy to improve the efficacy of T-DM1.