Blastoid Mantle Cell Lymphoma Presenting as an Oropharyngeal Mass.

Blastoid mantle cell lymphoma (MCL) is an extremely rare neoplasm with a dismal prognosis. MCL with an initial presentation in the oral cavity has been rarely reported. This report describes a 75-year-old male who presented with an oropharyngeal mass causing dysphonia and intermittent hypoxia. A biopsy and immunophenotyping confirmed MCL, favoring the blastoid variant. Imaging showed a 4.2 cm left oropharyngeal polypoid mass with extensive lymphadenopathy. His prognosis was considered unfavorable with elevated Ki-67 index, blastoid morphology, and p53 positivity of malignant cells. There was no central nervous system involvement. He received palliative radiation, resulting in profound tumor reduction and resolution of symptoms. An intensive chemoimmunotherapy was not deemed beneficial due to age, comorbidities, absence of TP53 mutation, and a personal preference for a less aggressive treatment. This case highlights the importance of risk-adapted and personalized management approaches in a very unique presentation of blastoid MCL.

Role and ethics of cynomolgus monkey (Macaca fascicularis) blastoids in primate developmental biology research.

This review on cynomolgus monkey (Macaca fascicularis) blastoids discusses a breakthrough in modeling early non-human primate embryogenesis, offering insights into embryonic development and implantation processes. It acknowledges ethical challenges and animal welfare considerations in developmental biology, suggests potential applications in human reproductive medicine, and highlights the need for ongoing ethical and technical refinement.

Genetic and prognostic analysis of blastoid and pleomorphic mantle cell lymphoma: a multicenter analysis in China.

Blastoid or pleomorphic mantle cell lymphoma (B/P-MCL) is characterized by high invasiveness and unfavorable outcomes, which is still a challenge for treating MCL. This retrospective study was performed to comprehensively analyze the clinical, genomic characteristics and treatment options of patients with B/PMCL from multicenter in China. Data were obtained from 693 patients with B/PMCL from three centers in China between April 1999 and December 2019. Seventy-four patients with BMCL (n = 43) or PMCL (n = 31) were included in the analysis. The median age of the cohort was 60.0 years with a male-to-female ratio of 2.89:1. The 3-year progression-free survival (PFS) and overall survival (OS) rates were 44.1% and 46.0%, respectively. Mutations of TP53, ATM, NOTCH1, NOTCH2, NSD2, SMARCA4, CREBBP, KMT2D, FAT1, and TRAF2 genes were the most common genetic changes in B/P-MCL. Progression of disease within 12 months (POD12) could independently predict the poor prognosis of patients with blastoid and pleomorphic variants. Patients with POD12 carried a distinct mutation profile (TP53, SMARCA4, NSD2, NOTCH2, KMT2D, PTPRD, CREBBP, and CDKN2A mutations) compared to patients with non-POD12. First-line high-dose cytosine arabinoside exposure obtained survival benefits in these populations, and BTKi combination therapy as the front-line treatment had somewhat improvement in survival with no significant difference in the statistic. In conclusion, B/P-MCL had inferior outcomes and a distinct genomic profile. Patients with POD12 displayed a distinct mutation profile and a poor prognosis. New therapeutic drugs and clinical trials for B/P-MCL need to be further explored.

SOX11+ Large B-Cell Neoplasms: Cyclin D1-Negative Blastoid/Pleomorphic Mantle Cell Lymphoma or Large B-Cell Lymphoma?

Large or blastoid B-cell neoplasms that are SOX11+ are a diagnostic dilemma and raise a differential diagnosis of cyclin D1-negative blastoid/pleomorphic mantle cell lymphoma (MCL) versus diffuse large B-cell lymphoma (DLBCL) or blastoid high-grade B-cell lymphoma (HGBL) with aberrant SOX11 expression. Here we report a study cohort of 13 SOX11+ large/blastoid B-cell neoplasms. Fluorescence in situ hybridization analysis was negative for CCND1 rearrangement in all 13 cases; 1 of 8 (12.5%) cases tested showed CCND2 rearrangement and 2 (25%) cases had extracopies of CCND2. Gene expression profiling showed that the study group had a gene expression signature similar to cyclin D1+ blastoid/pleomorphic MCL but different from DLBCL. Principal component analysis revealed that the cohort cases overlapped with cyclin D1+ blastoid/pleomorphic MCL but had minimal overlap with DLBCL. All patients in the cohort had clinicopathologic features similar to those reported for patients with cyclin D1+ MCL. We also performed a survey of SOX11 expression in a group of 85 cases of DLBCL and 24 cases of blastoid HGBL. SOX11 expression showed a 100% specificity and positive predictive value for the diagnosis of MCL. Overall, the results support the conclusion that large or blastoid B-cell neoplasms that are positive for SOX11 are best classified as cyclin D1-negative blastoid/pleomorphic MCL, and not as DLBCL or blastoid HGBL. We also conclude that SOX11 is a specific marker for the diagnosis of MCL, including cyclin D1-negative blastoid/pleomorphic MCL cases and should be performed routinely on blastoid/large B-cell neoplasms to help identify potential cases of cyclin D1-negative blastoid/pleomorphic MCL.

An expedition in the jungle of pluripotent stem cells of non-human primates.

For nearly three decades, more than 80 embryonic stem cell lines and more than 100 induced pluripotent stem cell lines have been derived from New World monkeys, Old World monkeys, and great apes. In this comprehensive review, we examine these cell lines originating from marmoset, cynomolgus macaque, rhesus macaque, pig-tailed macaque, Japanese macaque, African green monkey, baboon, chimpanzee, bonobo, gorilla, and orangutan. We outline the methodologies implemented for their establishment, the culture protocols for their long-term maintenance, and their basic molecular characterization. Further, we spotlight any cell lines that express fluorescent reporters. Additionally, we compare these cell lines with human pluripotent stem cell lines, and we discuss cell lines reprogrammed into a pluripotent naive state, detailing the processes used to attain this. Last, we present the findings from the application of these cell lines in two emerging fields: intra- and interspecies embryonic chimeras and blastoids.

The Clinicopathologic Features and Molecular Signatures of Blastoid High-Grade B Cell Lymphoma, Not Otherwise Specified.

A small subset of high-grade B-cell lymphoma (HGBL) with blastoid morphology remains poorly understood. We assessed 55 cases of blastoid HGBL, not otherwise specified (NOS) and compared their clinicopathologic characteristics with those of 81 non-blastoid HGBL-NOS and 62 blastoid HGBL with MYC and BCL2, with or without BCL6 rearrangements (double/triple-hit lymphoma [D/THL]). Patients with blastoid HGBL-NOS showed similar clinicopathologic features to patients with blastoid D/THLs and non-blastoid HGBL-NOS, except more frequently with a history of low-grade B-cell lymphoma, bone marrow involvement, and BCL2 rearrangement (P < .05) compared to the latter. MYC rearrangement (MYC-R), detected in 40% of blastoid HGBL-NOS, was associated with aggressive clinicopathologic features and poorer overall survival, even worse than that of blastoid D/THL (P < .05). Transcriptome profiling revealed a distinct gene expression pattern with differentially expressed genes enriched in MYC and P53-targeted genes in MYC-R blastoid HGBL-NOS. Fifty-two percent of blastoid HGBL-NOS had a double hit-like signature, similar to non-blastoid HGBL-NOS (P = .73). The overall survival of the blastoid HGBL-NOS group was similar to that of the blastoid D/THL group but appeared poorer than that of its non-blastoid counterparts (P = .07). Taken together, blastoid HGBL-NOS is an aggressive B-cell lymphoma that shares overlapping clinicopathologic and genetic features with non-blastoid HGBL-NOS. MYC-R in patients with blastoid HGBL-NOS identifies a highly aggressive subgroup with distinct aggressive clinicopathologic features, unique molecular signatures, and a dismal clinical outcome.

3D-cultured blastoids model human embryogenesis from pre-implantation to early gastrulation stages.

Naive human pluripotent stem cells have the remarkable ability to self-organize into blastocyst-like structures ("blastoids") that model lineage segregation in the pre-implantation embryo. However, the extent to which blastoids can recapitulate the defining features of human post-implantation development remains unexplored. Here, we report that blastoids cultured on thick three-dimensional (3D) extracellular matrices capture hallmarks of early post-implantation development, including epiblast lumenogenesis, rapid expansion and diversification of trophoblast lineages, and robust invasion of extravillous trophoblast cells by day 14. Extended blastoid culture results in the localized activation of primitive streak marker TBXT and the emergence of embryonic germ layers by day 21. We also show that the modulation of WNT signaling alters the balance between epiblast and trophoblast fates in post-implantation blastoids. This work demonstrates that 3D-cultured blastoids offer a continuous and integrated in vitro model system of human embryonic and extraembryonic development from pre-implantation to early gastrulation stages.

Skin Involvement by Hematological Neoplasms with Blastic Morphology: Lymphoblastic Lymphoma, Blastoid Variant of Mantle Cell Lymphoma and Differential Diagnoses.

Hematological neoplasms sharing a blastic morphology may involve the skin. The skin may be either the primary site of occurrence of hematological malignancies with blastic features or cutaneous lesions are the first manifestation of an underlying systemic malignancy. The assessment of skin biopsies of hematological neoplasms with blastic features poses diagnostic problems and requires expert hematopathologists considering a wide range of differential diagnoses. The precise diagnosis of diseases sharing blastic features but with different outcomes and requiring distinct therapies is essential for patient management. The present paper mainly focuses on cutaneous involvement of the blastoid variant of mantle cell lymphoma and lymphoblastic lymphoma of B-cell or T-cell origin. The relevant literature has been reviewed and the clinical aspects, pathological features, prognosis, and therapy of both blastoid mantle cell lymphoma and lymphoblastic lymphoma involving the skin are discussed. A focus on other hematological entities with blastic features, which may involve the skin, to be taken into consideration in differential diagnosis is also given.

Cynomolgus monkey embryo model captures gastrulation and early pregnancy.

Human stem cell-derived blastoids display similar morphology and cell lineages to normal blastocysts. However, the ability to investigate their developmental potential is limited. Here, we construct cynomolgus monkey blastoids resembling blastocysts in morphology and transcriptomics using naive ESCs. These blastoids develop to embryonic disk with the structures of yolk sac, chorionic cavity, amnion cavity, primitive streak, and connecting stalk along the rostral-caudal axis through prolonged in vitro culture (IVC). Primordial germ cells, gastrulating cells, visceral endoderm/yolk sac endoderm, three germ layers, and hemato-endothelial progenitors in IVC cynomolgus monkey blastoids were observed by single-cell transcriptomics or immunostaining. Moreover, transferring cynomolgus monkey blastoids to surrogates achieves pregnancies, as indicated by progesterone levels and presence of early gestation sacs. Our results reveal the capacity of in vitro gastrulation and in vivo early pregnancy of cynomolgus monkey blastoids, providing a useful system to dissect primate embryonic development without the same ethical concerns and access challenges in human embryo study.

Bilineage embryo-like structure from EPS cells can produce live mice with tetraploid trophectoderm.

Self-organized blastoids from extended pluripotent stem (EPS) cells possess enormous potential for investigating postimplantation embryo development and related diseases. However, the limited ability of postimplantation development of EPS-blastoids hinders its further application. In this study, single-cell transcriptomic analysis indicated that the "trophectoderm (TE)-like structure" of EPS-blastoids was primarily composed of primitive endoderm (PrE)-related cells instead of TE-related cells. We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure. Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation. Furthermore, we demonstrated that blastocyst-like structures reconstituted by combining the EPS-derived bilineage embryo-like structure (BLES) with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses. In summary, our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.

Combining Endometrial Assembloids and Blastoids to Delineate the Molecular Roadmap of Implantation.

Implantation is the process by which a competent blastocyst burrows into the receptive uterus to support embryo development. Successful implantation is of the utmost importance to pregnancy. However, due to the short window and difficulty in accessing the uterus in vivo during implantation, including ethical considerations, our understanding of the molecular network that safeguards this process remains incomplete. The use of three-dimensional (3D) culture systems has significant advantages as it recapitulates many aspects of the tissue organization and cell composition seen in vivo. With the recent advent of endometrial organoids and blastoids, it is now feasible to establish an in vitro implantation culture model to dissect the molecular signaling networks that are critical for implantation. In this review, we briefly summarize the current methodology for generating endometrial organoids and blastoids, along with the applications of these organoids for research on implantation. Incorporating stromal and immune cells, blood vessels, and others into the current endometrial organoid could build a more complete model of the endometrium, which can be combined with blastoids to model blastocyst implantation in vitro. We envision that this novel 3D system can be employed to elucidate the molecular mechanisms required for successful implantation.

Comparative assessment of embryotoxicity of 2,4,6-triiodophenol to mouse blastoid and pre-implantation embryo models.

Embryonic developmental effects of disinfection by-products, which are generated during drinking water treatment and widely detected in environment, have gained more and more attention nowadays, calling for construction of in vitro research models which can mimic early embryonic development to evaluate the embryotoxicity. The embryonic stem cell test offers a promising assay to predict embryotoxicity of environmental pollutions. However, it is not appropriate for the toxicological study of preimplantation embryos. Here, we used mouse extended stem cells (mEPS) to reconstruct embryo-like structures (blastoid), furtherly attempting to evaluate the reliability of this model for the prediction of possible developmental toxicity of 2,4,6-triiodophenol (TIP, 5-50 µM), a novel halogenated disinfection byproduct widely detected in water and even drinking water, to mammalian preimplantation embryo. To verify this, we treated mouse embryo derived from in vitro fertilization (IVF-embryo) as reference. The results showed that mEPS-blastoid was like natural blastocyst in morphology, cell composition, and could recapitulate key developmental events happened during mouse preimplantation stage. When blastoid and IVF-embryo models were separately exposed to TIP, their final blastocyst formation rates were not impaired, according to morphological features, meanwhile that TIP exposure caused slight cell apoptosis. Besides, TIP induced an ICM cell bias in cell fate decision, resulting in cell proportion change, which implied abnormal developmental potential. Though we could not evaluate TIP's embryotoxicity before 8-cell stage using blastoid model, its viability as a novel and high-throughput assessment platform for increasing environmental pollutants was still recognized.

Blastoid B-Cell Neoplasms: Diagnostic Challenges and Solutions.

Blastoid B-cell neoplasms mainly include B-lymphoblastic leukemia/lymphoma (B-ALL), blastoid mantle cell lymphoma, and high-grade B-cell lymphoma with blastoid morphologic features (blastoid HGBL). Distinguishing blastoid HGBL from B-ALL can be challenging and we previously developed six-point flow cytometry-focused and three-point immunohistochemistry-focused scoring systems to aid in differential diagnosis. However, the six-point scoring system was derived from bone marrow cases and occasional cases may have a misleading score using either system. In this study, we assessed 121 cases of blastoid-HGBL (37 BM and 84 extramedullary) to validate the six-point scoring system in all tissue types and to further compare the two scoring systems. Compared with 47 B-ALL cases enriched for CD34-negative neoplasm, the 121 blastoid-HGBL cases showed distinctive pathologic features. The six-point scoring system showed a sensitivity of 100%. A comparison of the two scoring systems in blastoid HGBL (n = 64) and B-ALL (n = 37) showed a concordance score rate of 88%. Thirteen cases showed misleading scores, including five HGBL and eight B-ALL, and the diagnosis was further validated by gene transcriptome profiling. Twelve of thirteen cases had discordant scores between the two scoring systems. Simultaneous employment of both scoring systems improved the accuracy of classification of blastoid B-cell neoplasms to 99%. In conclusion, the previously defined six-point scoring system showed an excellent performance regardless of the tissue origin. Using both scoring systems together improves the accuracy of classification of blastoid B-cell neoplasms. Cases with discordant scores between the two scoring systems were extremely challenging neoplasms and classification required correlation with all available clinical and genetic features.

Biophysical models of early mammalian embryogenesis.

Embryo development is a critical and fascinating stage in the life cycle of many organisms. Despite decades of research, the earliest stages of mammalian embryogenesis are still poorly understood, caused by a scarcity of high-resolution spatial and temporal data, the use of only a few model organisms, and a paucity of truly multidisciplinary approaches that combine biological research with biophysical modeling and computational simulation. Here, we explain the theoretical frameworks and biophysical processes that are best suited to modeling the early mammalian embryo, review a comprehensive list of previous models, and discuss the most promising avenues for future work.

Human embryoids: A new strategy of recreating the first steps of embryonic development in vitro.

Molecular mechanisms surrounding early human embryonic events such as blastocyst formation, implantation, and the specification of the body axes are some of the most attractive research questions of developmental biology today. A knowledge on the detailed signaling landscape underlying these critical events in the human could impact the way we treat early pregnancy disorders and infertility, and considerably advance our abilities to make precise human tissues in a lab. However, owing to ethical, technical, and policy restrictions, research on early human embryo development historically stalled behind animal models. The rapid progress in 3D culture of human embryonic stem cells over the past years created an opportunity to overcome this critical challenge. We review recently developed strategies of making 3D models of the human embryo built from embryonic stem cells, which we refer to as embryoids. We focus on models aimed at reconstituting the 3D epithelial characteristics of the early human embryo, namely the intra/extraembryonic signaling crosstalk, tissue polarity, and embryonic cavities. We identify distinct classes of embryoids based on whether they explicitly include extraembryonic tissues and we argue for the merit of compromising on certain aspects of embryo mimicry in balancing the experimental feasibility with ethical considerations. Human embryoids open gates toward a new field of synthetic human embryology, allowing to study the long inaccessible stages of early human development at unprecedented detail.

Bilineage embryo-like structure from EPS cells can produce live mice with tetraploid trophectoderm

Self-organized blastoids from extended pluripotent stem (EPS) cells possess enormous potential for investigating postimplantation embryo development and related diseases. However, the limited ability of postimplantation development of EPS-blastoids hinders its further application. In this study, single-cell transcriptomic analysis indicated that the "trophectoderm (TE)-like structure" of EPS-blastoids was primarily composed of primitive endoderm (PrE)-related cells instead of TE-related cells. We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure. Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation. Furthermore, we demonstrated that blastocyst-like structures reconstituted by combining the EPS-derived bilineage embryo-like structure (BLES) with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses. In summary, our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.

Stem cell-based models of early mammalian development.

The complex process by which a single-celled zygote develops into a viable embryo is nothing short of a miraculous wonder of the natural world. Elucidating how this process is orchestrated in humans has long eluded the grasp of scientists due to ethical and practical limitations. Thankfully, pluripotent stem cells that resemble early developmental cell types possess the ability to mimic specific embryonic events. As such, murine and human stem cells have been leveraged by scientists to create in vitro models that aim to recapitulate different stages of early mammalian development. Here, we examine the wide variety of stem cell-based embryo models that have been developed to recapitulate and study embryonic events, from pre-implantation development through to early organogenesis. We discuss the applications of these models, key considerations regarding their importance within the field, and how such models are expected to grow and evolve to achieve exciting new milestones in the future.

In vitro models of human development and their potential application in developmental toxicity testing.

Recent publications describe the development of in vitro models of human development, for which applications in developmental toxicity testing can be envisaged. To date, these regulatory assessments have exclusively been performed in animal studies, the relevance of which to adverse reactions in humans may be questioned. Recently developed cell culture-based models of embryo-fetal development, however, do not yet exhibit sufficient levels of standardisation and reproducibility. Here, the advantages and shortcomings of both in vivo and in vitro developmental toxicity testing are addressed, as well as the possibility of integrated testing strategies as a viable option in the near future.

Epiblast inducers capture mouse trophectoderm stem cells in vitro and pattern blastoids for implantation in utero.

The embryo instructs the allocation of cell states to spatially regulate functions. In the blastocyst, patterning of trophoblast (TR) cells ensures successful implantation and placental development. Here, we defined an optimal set of molecules secreted by the epiblast (inducers) that captures in vitro stable, highly self-renewing mouse trophectoderm stem cells (TESCs) resembling the blastocyst stage. When exposed to suboptimal inducers, these stem cells fluctuate to form interconvertible subpopulations with reduced self-renewal and facilitated differentiation, resembling peri-implantation cells, known as TR stem cells (TSCs). TESCs have enhanced capacity to form blastoids that implant more efficiently in utero due to inducers maintaining not only local TR proliferation and self-renewal, but also WNT6/7B secretion that stimulates uterine decidualization. Overall, the epiblast maintains sustained growth and decidualization potential of abutting TR cells, while, as known, distancing imposed by the blastocyst cavity differentiates TR cells for uterus adhesion, thus patterning the essential functions of implantation.