5G2 mutant mice model loss of a commonly deleted segment of chromosome 7q22 in myeloid malignancies.

Monosomy 7 and del(7q) are among the most common and poorly understood genetic alterations in myelodysplastic neoplasms and acute myeloid leukemia. Chromosome band 7q22 is a minimally deleted segment in myeloid malignancies with a del(7q). However, the rarity of "second hit" mutations supports the idea that del(7q22) represents a contiguous gene syndrome. We generated mice harboring a 1.5 Mb germline deletion of chromosome band 5G2 syntenic to human 7q22 that removes Cux1 and 27 additional genes. Hematopoiesis is perturbed in 5G2+/del mice but they do not spontaneously develop hematologic disease. Whereas alkylator exposure modestly accelerated tumor development, the 5G2 deletion did not cooperate with KrasG12D, NrasG12D, or the MOL4070LTR retrovirus in leukemogenesis. 5G2+/del mice are a novel platform for interrogating the role of hemopoietic stem cell attrition/stress, cooperating mutations, genotoxins, and inflammation in myeloid malignancies characterized by monosomy 7/del(7q).

Variability in biopsy quality informs translational research applications in hepatocellular carcinoma.

In the era of precision medicine, biopsies are playing an increasingly central role in cancer research and treatment paradigms; however, patient outcomes and analyses of biopsy quality, as well as impact on downstream clinical and research applications, remain underreported. Herein, we report biopsy safety and quality outcomes for percutaneous core biopsies of hepatocellular carcinoma (HCC) performed as part of a prospective clinical trial. Patients with a clinical diagnosis of HCC were enrolled in a prospective cohort study for the genetic, proteomic, and metabolomic profiling of HCC at two academic medical centers from April 2016 to July 2020. Under image guidance, 18G core biopsies were obtained using coaxial technique at the time of locoregional therapy. The primary outcome was biopsy quality, defined as tumor fraction in the core biopsy. 56 HCC lesions from 50 patients underwent 60 biopsy events with a median of 8 core biopsies per procedure (interquartile range, IQR, 7-10). Malignancy was identified in 45/56 (80.4%, 4 without pathology) biopsy events, including HCC (40/56, 71.4%) and cholangiocarcinoma (CCA) or combined HCC-CCA (5/56, 8.9%). Biopsy quality was highly variable with a median of 40% tumor in each biopsy core (IQR 10-75). Only 43/56 (76.8%) and 23/56 (41.1%) samples met quality thresholds for genomic or metabolomic/proteomic profiling, respectively, requiring expansion of the clinical trial. Overall and major complication rates were 5/60 (8.3%) and 3/60 (5.0%), respectively. Despite uniform biopsy protocol, biopsy quality varied widely with up to 59% of samples to be inadequate for intended purpose. This finding has important consequences for clinical trial design and highlights the need for quality control prior to applications in which the presence of benign cell types may substantially alter findings.

Hepatitis C viraemic organs in solid organ transplantation.

Although rates of organ donation and solid organ transplantation have been increasing over the last few decades, demand for organs still greatly exceeds supply. Several strategies have been utilised to increase organ supply, including utilisation of high-risk (e.g. HCV antibody-positive) donors. In this context, organs from HCV antibody-positive donors have been used in recipients with chronic HCV since the early 1990s. Recently, transplantation of HCV-viraemic organs into HCV-naïve recipients has garnered significant interest, owing to the development of safe and highly effective direct-acting antivirals and increased experience of treating HCV in the post-transplant setting. Preliminary studies based largely in the US have shown excellent outcomes in kidney, liver, heart, and lung transplantation. This practice has the potential to significantly increase transplantation rates and decrease waitlist mortality; however, intentionally transmitting an infectious disease to recipients has important practical and ethical implications. Further, the generalisability of the US experience to other countries is limited by significant differences in HCV-viraemic donor populations. This review summarises the current data on this practice, discusses barriers to implementation, and highlights areas that warrant further study.

Effect of Nonalcoholic Fatty Liver Disease and Metabolic Risk Factors on Waitlist Outcomes in Patients With Hepatocellular Carcinoma.

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of hepatocellular carcinoma (HCC) in the United States. Prior data suggest that NAFLD-HCC patients are less likely to receive liver transplantation (LT) and have worse overall survival; however, the reason for this discrepancy is unknown. METHODS: We conducted a retrospective study of 631 HCC patients listed for LT at a large academic center from 2004 to 2013. Waitlist dropout and LT were analyzed using competing risk regression. RESULTS: Compared with other-HCC patients (n = 589), NAFLD-HCC patients (n = 42, 6.7%) were older (65 versus 58, P < 0.001) with more women (50.0 versus 23.6%, P < 0.001), Hispanic ethnicity (40.5 versus 17.7%, P = 0.001), obesity (69.0 versus 29.9%, P < 0.001), diabetes mellitus (59.5 versus 27.8%, P < 0.01), insulin-dependence (23.8 versus 10.2%, P = 0.007), hyperlipidemia (40.5 versus 10.5, P < 0.001), and statin use (33.3 versus 5.3%, P < 0.001). Cumulative incidence of waitlist dropout at 2 y was 17.4% (95% confidence intervals, 7.7-30.4) for NAFLD HCC and 25.4% (95% confidence intervals, 21.9-29.0) for other HCC (P = 0.28). No difference in waitlist dropout or receipt of LT between NAFLD HCC and other HCC was found on regression analysis. Similarly, NAFLD and obesity, obesity alone, diabetes mellitus, insulin-dependence, hyperlipidemia, and statin use were not associated with waitlist outcomes. Finally, we observed no statistically significant difference in 5-y survival from HCC diagnosis between NAFLD HCC and other HCC (78.5% versus 66.9%, P = 0.9). CONCLUSIONS: In our single-center cohort, we observed no difference in waitlist outcomes or survival in NAFLD HCC, although conclusions are limited by the small number of NAFLD-HCC patients. Notably, the inclusion of patients with obesity in the NAFLD-HCC group and stratification by individual metabolic factors also showed no difference in waitlist outcomes.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Current Status and Implications for Liver Transplantation.

PURPOSE OF REVIEW: Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) are both pulmonary vascular complications of advanced liver disease; however, these syndromes have distinct pathophysiology, clinical implications, and management. RECENT FINDINGS: While both conditions are associated with portal hypertension, HPS results from diffuse pulmonary capillary vasodilation and PoPH results from vasoconstriction and vascular remodeling of pulmonary arteries. In HPS, no medical therapies clearly improve outcomes; however, patients have excellent post-LT outcomes with near uniform reversal of hypoxemia. In PoPH, several medical therapies used in idiopathic pulmonary hypertension have been shown improve pulmonary hemodynamics, symptoms, and potentially LT outcomes; however, further study is needed to determine best treatment regimens, long-term outcomes on medical therapy, and role of LT. SUMMARY: While HPS results in severe hypoxemia that is usually reversible by LT, PoPH patients develop progressive pulmonary hypertension that may improve with medical therapy.

Functional evidence implicating chromosome 7q22 haploinsufficiency in myelodysplastic syndrome pathogenesis.

Chromosome 7 deletions are highly prevalent in myelodysplastic syndrome (MDS) and likely contribute to aberrant growth through haploinsufficiency. We generated mice with a heterozygous germ line deletion of a 2-Mb interval of chromosome band 5A3 syntenic to a commonly deleted segment of human 7q22 and show that mutant hematopoietic cells exhibit cardinal features of MDS. Specifically, the long-term hematopoietic stem cell (HSC) compartment is expanded in 5A3(+/del) mice, and the distribution of myeloid progenitors is altered. 5A3(+/del) HSCs are defective for lymphoid repopulating potential and show a myeloid lineage output bias. These cell autonomous abnormalities are exacerbated by physiologic aging and upon serial transplantation. The 5A3 deletion partially rescues defective repopulation in Gata2 mutant mice. 5A3(+/del) hematopoietic cells exhibit decreased expression of oxidative phosphorylation genes, increased levels of reactive oxygen species, and perturbed oxygen consumption. These studies provide the first functional data linking 7q22 deletions to MDS pathogenesis.

Prolonged Remission in Neuromyelitis Optica Following Cessation of Rituximab Treatment.

Neuromyelitis optica is an autoimmune disease characterized by acute episodes of transverse myelitis and optic neuritis. Several small, open-label studies suggest rituximab, a monoclonal antibody against CD20, prevents relapses in neuromyelitis optica; however, there is little consensus on timing or duration of treatment. Here we report four patients with severe relapsing neuromyelitis optica who were stabilized on rituximab and, after discontinuing treatment, continued to experience prolonged remission of their disease. Remission ranged from 4.5 to 10.5 years total, including 3 to 9 years off all therapies. The patients had sustained clinical responses despite normal B-lymphocyte levels and, in at least 2 patients, continued seropositivity for aquaporin-4 antibodies. These cases suggest that rituximab may induce prolonged remission in certain neuromyelitis optica patients, and they highlight the need for further elucidation of rituximab's mechanism in neuromyelitis optica.

Protective environmental factors for neuromyelitis optica.

OBJECTIVE: To determine whether early environmental factors, such as cesarean delivery, breastfeeding, and exposure to smoking or herpes viruses, are associated with neuromyelitis optica (NMO) risk in children. METHODS: This is a case-control study of pediatric NMO, multiple sclerosis (MS), and healthy subjects. Early-life exposures were obtained by standardized questionnaire. Epstein-Barr virus, cytomegalovirus, and herpes simplex virus 1 antibody responses were determined by ELISA. Multivariate logistic regression models were used to adjust for age at sampling, sex, race, and ethnicity. RESULTS: Early-life exposures were obtained from 36 pediatric subjects with NMO, 491 with MS, and 224 healthy controls. Daycare (odds ratio [OR] 0.33, 95% confidence interval [CI] 0.14, 0.78; p < 0.01) and breastfeeding (OR 0.42, 95% CI 0.18, 0.99; p = 0.05) were associated with lower odds of having NMO compared with healthy subjects. Cesarean delivery tended to be associated with 2-fold-higher odds of NMO compared with having MS/clinically isolated syndrome (OR 1.98, 95% CI 0.88, 4.59; p = 0.12) or with being healthy (OR 1.95, 95% CI 0.81, 4.71; p = 0.14). Sera and DNA were available for 31 subjects with NMO, 189 with MS, and 94 healthy controls. Epstein-Barr virus, herpes simplex virus 1, cytomegalovirus exposure, and being HLA-DRB1*15 positive were not associated with odds of having NMO compared with healthy subjects. CONCLUSIONS: Exposure to other young children may be an early protective factor against the development of NMO, as previously reported for MS, consistent with the hypothesis that infections contribute to disease risk modification. Unlike MS, pediatric NMO does not appear to be associated with exposures to common herpes viruses.

Use of chromosome engineering to model a segmental deletion of chromosome band 7q22 found in myeloid malignancies.

Monosomy 7 and del(7q) are associated with adverse features in myeloid malignancies. A 2.5-Mb commonly deleted segment (CDS) of chromosome band 7q22 is implicated as harboring a myeloid tumor suppressor gene (TSG); however, molecular analysis of candidate TSGs has not uncovered loss of function. To determine whether haploinsufficiency for the 7q22 CDS contributes to myeloid leukemogenesis, we performed sequential gene targeting to flank a region of orthologous synteny on mouse chromosome band 5A3 with loxP sites. We then generated Mx1-Cre, 5A3(fl) mutant mice and deleted the targeted interval in vivo. Although excision was inefficient, we confirmed somatic deletion of the 5A3 CDS in the hematopoietic stem cell compartment. Mx1-Cre, 5A3(fl) mice show normal hematologic parameters and do not spontaneously develop myeloid malignancies. The 5A3(fl) deletion does not cooperate with oncogenic Kras(G12D) expression, Nf1 inactivation, or retroviral mutagenesis to accelerate leukemia development and did not modulate responsiveness to antileukemia drugs. These studies demonstrate that it is feasible to somatically delete a large chromosomal segment implicated in tumor suppression in hematopoietic cell populations in vivo; however, our data do not support the hypothesis that the 7q22/5A3 CDS interval contains a myeloid TSG.