IKZF1 Deletion Subtyping and Outcome Analysis in BCR–ABL1-Negative Pediatric B-Cell Acute Lymphoblastic Leukemia: A Single-Institution Experience from North India

BackgroundIKZF1 deletions are associated with adverse outcomes in B-cell acute lymphoblastic leukemia (B-ALL). We assessed the prevalence and clinical impact of functional subtypes of IKZF1 deletions in pediatric BCR–ABL1-negative B-ALL. Patients andMethodsThis retrospective study of IKZF1 deletions was done in cases of pediatric BCR–ABL1-negative B-ALL. The genomic DNA of cases, over a 53-month period, was analyzed using multiplex ligation-dependent probe amplification and multiplex fluorescent polymerase chain reaction. The deletions were divided into functional subgroups: (1) loss-of-function/haploinsufficiency, (2) dominant-negative, and (3) a combination of both types of deletion. The post-induction remission status, event-free survival (EFS), and overall survival (OS) were noted.ResultsOut of 320 cases, 47 (14.7%) had IKZF1 deletions. Thirty-six of the 47 (77%) had loss-of-function deletions, 10 (21%) had dominant-negative deletions, and one (2%) had a combination of both types. The post-induction remission rates in cases with loss-of-function deletions (22/30, 73%; P = .060) and dominant-negative deletions (4/5, 80%; P = .517) were lower compared with those without deletions (215/248, 86.7%). These cases also had worse median EFS: 21.1 months (P = .006) for loss-of-function and 15.4 months (P = .156) for dominant-negative deletions, compared with 46.4 months in cases without IKZF1 deletions. They also had worse median OS: 23.4 months (P = .012) for loss-of-function deletions and 15.7 months (P = .233) for dominant-negative deletions, compared with median not reached in cases without IKZF1 deletions.ConclusionThe IKZF1 deletions were seen in 14.7% of BCR–ABL1-negative pediatric B-ALL. Most of these deletions (77%) were loss-of-function type. The cases with loss-of-function deletions had lower remission rates and poor EFS and OS compared with cases without IKZF1 deletions. A similar trend of poor outcome was seen in the few cases with dominant-negative IKZF1 deletions.     

Treatment of posterior cruciate ligament tibial avulsion by a minimally-invasive open posterior approach

ObjectiveTo assess the surgical technique and report the outcomes following fixation of PCL bony avulsions through mini-invasive posterior knee approach as described by Burks and Schaffer.MethodsFrom June 2012 to July 2015, 27 patients enrolled in the study (21 males and 6 females). Fixation of tibial PCL avulsion fractures was done with one or two cannulated screws, or sutures through Burks and Schaffer’s approach. The mean interval before surgery was 16 days (1–70) .Patients was followed up for an average of 51 weeks. The outcome measures evaluated at final follow-up were (1) clinical stability as assessed by posterior drawer test, (2) radiologic union, (3) functional assessment by Lysholm score, and (4) gastrocnemius muscle strength as a measure of morbidity.ResultsAverage operative time was 43 min. Improvement of both subjective Lysholm score (mean 93) and objective stability testing by posterior drawer test (returns to normal in 81.1% of patients) at the final follow-up. Good radiographic union at average of 5.6 weeks. No morbidity of the gastrocnemius with few complications.ConclusionsThe approach was fast and safe with excellent visualization. It allows surgeons to address other injuries in the same setting. It can be considered as a minimally-invasive open surgery without surgery-related morbidity. It is a reproducible technique that can be done at any trauma centre by surgeons with average experience. The subjective and objective results of the technique are excellent and comparable to the arthroscopic procedures that needs more specific centres with well-trained surgeons.     

NUT carcinoma of the lung

NUT carcinoma of the thorax is a rare and very aggressive tumor, whose definition is based on the demonstration of a nuclear protein in testis (NUTM1; also known as NUT) gene fusion on 15q14 with different partners from the bromodomain-containing proteins gene family. This fusion results in an activation of MYC oncoprotein responsible for the tumor's aggressivity. NUT carcinoma arises preferentially in young adults, presenting a large thoracic mass frequently associated with lymph nodes, bone or pleural metastases. At histology, this tumor is often poorly differentiated, mainly composed of sheets of small cells with scant cytoplasm, a round nucleus with a central nucleolus. Focal areas of squamous differentiation can be observed. Mitoses and necrosis are frequent, as well as neutrophilic infiltrate. The diagnosis is based on the detection of NUT protein expression by immunohistochemistry using the rabbit monoclonal antibody C52B1 in more than 50% of the tumor nuclei. This technique offers 87% sensitivity and nearly 100% specificity with reference to FISH or RT-PCR, which confirm the NUTM1 rearrangement. The differential diagnoses include basaloid carcinoma of the lung, small cell carcinoma, thymic carcinoma (basaloid variant), SMARCA4_deficient thoracic sarcoma, other NUTM1 rearranged undifferentiated tumors, small round cell tumors, non-Hodgkin lymphoma/leukemia, and melanoma. The prognosis of NUT carcinoma remains very poor, with a median survival of 6.7 months, and 1- and 2-year overall survival rates of 30% and 19%, respectively. NUT carcinoma is often refractory to conventional chemotherapy, but ifosfamide-based regimens or BET inhibitors could represent promising therapies.     

Rabdomiosarcoma infantil

Rhabdomyosarcoma is the most common soft-tissue sarcoma in children; it can appear in any part of the body. Its biological behavior varies widely, and despite the absence of specific clinical or radiological characteristics, rhabdomyosarcoma should be taken into account in the differential diagnosis of solid tumors in children. This review focuses primarily on the imaging findings and anatomical distribution of the histological subtypes of childhood rhabdomyosarcoma and secondarily on the differential findings in histological studies.     

Second malignancies in multiple myeloma; emerging patterns and future directions

The changing landscape of treatment options for multiple myeloma has led to a higher proportion of patients achieving deep, long-lasting responses to therapy. With the associated improvement in overall survival, the development of subsequent second malignancies has become of increased significance. The risk of second malignancy after multiple myeloma is affected by a combination of patient-, disease- and therapy-related risk factors. This review discusses recent data refining our knowledge of these contributing factors, including current treatment modalities which increase risk (i.e. high-dose melphalan with autologous stem cell transplant and lenalidomide maintenance therapy). We highlight emerging data towards individualized risk- and response-adapted treatment strategies and discuss key areas requiring future research.     

Lineage-related and particle size-dependent cytotoxicity of chitosan nanoparticles on mouse bone marrow-derived hematopoietic stem and progenitor cells

Chitosan nanoparticles (CSNPs) have potential applications in stem cell research. In this study, ex vivo cytotoxicity of CSNPs on mouse bone marrow-derived (MBMCs) hematopoietic stem and progenitor cells (HSPCs) was determined. MBMCs were exposed to CSNPs of different particle sizes at various concentrations for up to 72 h. Cytotoxicity effect of CSNPs on MBMCs was determined using MTT, Live/Dead Viability/Cytotoxicity assays and flow cytometry analysis of surface antigens on HSCs (Sca-1⁺), myeloid-committed progenitors (CD11b⁺, Gr-1⁺), and lymphoid-committed progenitors (CD45⁺, CD3e⁺). At 24 h incubation, MBMCs' viability was not affected by CSNPs. At 48 and 72 h, significant reduction was detected at higher CSNPs concentrations. Small CSNPs (200 nm) significantly reduced MBMCs' viability while medium-sized particle (∼400 nm) selectively promoted MBMCs growth. Surface antigen assessment demonstrated lineage-dependent effect. Significant decrease in Sca-1⁺ cells percentage was observed for medium-sized particle at the lowest CSNPs concentration. Meanwhile, reduction of CD11b⁺ and Gr-1⁺ cells percentage was detected at high and intermediate concentrations of medium-sized and large CSNPs. Percentage of CD45⁺ and CD3e⁺ cells along with ROS levels were not significantly affected by CSNPs. In conclusion, medium-sized and large CSNPs were relatively non-toxic at lower concentrations. However, further investigations are necessary for therapeutic applications.     

Skin barrier disruptions in tape stripped and allergic dermatitis models have no effect on dermal penetration and systemic distribution of AHAPS-functionalized silica nanoparticles

The skin is a potential site of entry for nanoparticles (NP) but the role of disease-associated barrier disturbances on the path and extent of skin penetration of NP remains to be characterized. Silica nanoparticles (SiO₂-NP) possess promising potential for various medical applications. Here, effects of different skin barrier disruptions on the penetration of N-(6-aminohexyl)-aminopropyltrimethoxysilane (AHAPS) functionalized SiO₂-NP were studied. AHAPS-SiO₂-NP (55 ± 6 nm diameter) were topically applied on intact, tape stripped or on inflamed skin of SKH1 mice with induced allergic contact dermatitis for one or five consecutive days, respectively. Penetration of AHAPS-SiO₂-NP through the skin was not observed regardless of the kind of barrier disruption. However, only after subcutaneous injection, AHAPS-SiO₂-NP were incorporated by macrophages and transported to the regional lymph node only. Adverse effects on cells or tissues were not observed. In conclusion, AHAPS-SiO₂-NP seem to not cross the normal or perturbed mouse skin.From the Clinical EditorSkin is a potential site of entry for nanoparticles; however, it is poorly understood how skin diseases may alter this process. In tape-stripped skin and allergic contact dermatitis models the delivery properties of AHAPS-SiO2 nanoparticles remained unchanged, and in neither case were these NP-s able to penetrate the skin. No adverse effects were noted on the skin in these models and control mice.