Tumor Of Immature Cells Research Articles

Tumor heterogeneity from the viewpoint of pathologists.

Morphological and functional heterogeneity are found in tumors, with the latter reflecting the different levels of resistance against antitumor therapies. In a therapy-resistant subpopulation, the expression levels of differentiation markers decrease, and those of immature markers increase. In addition, this subpopulation expresses genes involved in drug metabolism, such as aldehyde dehydrogenase 1A1 (ALDH1A1). Because of their similarity to stem cells, cells in the latter therapy-resistant subpopulation are called cancer stem cells (CSCs). Like normal stem cells, CSCs were originally thought not to arise from non-CSCs, but this hierarchical model is too simple. It is now believed that CSCs are generated from non-CSCs. The plasticity of tumor phenotypes between CSCs and non-CSCs causes difficulty in completely curing tumors. In this review, focusing on ALDH1A1 as a marker for CSCs or immature tumor cells, the dynamics of ALDH1A1-expressing tumor cells and their regulatory mechanisms are described, and the plausible regulatory mechanisms of plasticity of ALDH1A1 expression phenotype are discussed. Genetic mutations are a significant factor for tumorigenesis, but non-mutational epigenetic reprogramming factors yielding tumor heterogeneity are also crucial in determining tumor characteristics. Factors influencing non-mutational epigenetic reprogramming in tumors are also discussed.

Abstract 1678: Single-cell landscape of the TH-MYCN neuroblastoma mouse model

Abstract Background and aims: Neuroblastoma (NB) is the most common and deadly malignancy of infancy. It is an embryonal neuroendocrine tumor arising from the neural crest lineage. Amplification of MYCN is a frequent genetic abnormality, found in approximately 20% of NB tumors, and represents a critical stratifying prognostic marker. Given that MYCN plays a key role in NB tumorigenesis and aggressiveness, the TH-MYCN transgenic mouse model is widely used in NB research. This model is characterized by the overexpression of MYCN in neuroectodermal cells, driven by tyrosine hydroxylase (TH) promoter. This overexpression gives rise to tumors exclusively in the sympathoadrenal system, reflecting human NB features. We aimed to explore the transcriptional landscape of TH-MYCN tumors by single-cell RNA sequencing (scRNA-seq). Methods: Tumors from three homozygous and two hemizygous TH-MYCN mice were dissociated into single cells, profiled by scRNA-seq (Chromium 3’ v2 kit, 10x Genomics), sequenced on the NextSeq platform (Illumina). A total of 41666 single cells were analyzed using pagoda2 and conos. TH-MYCN tumor single-cell transciptomes were further aligned with previously published transcriptomes from the adrenal gland of three mice at embryonic day (E)13.5. To evaluate malignant tumor cells, copy number variants (CNV) were analyzed using inferCNV. Immunohistochemistry was used to validate the bioinformatically predicted cell types. Results: scRNA-seq of tumors from TH-MYCN mice revealed 16 major cell populations, spanning stromal, immune and tumor compartments. MYCN+ tumor cells predominantly resemble sympathetic neuroblasts (Isl1, Stmn1, Nefl, Nefm), while MYCN+ chromaffin-like tumor cells (Pnmt, Cdkn1c, Th, Dbh) were rare. Immunofluorescence stainings confirmed that tumors predominantly consist of proliferating sympathetic neuroblasts. Tumor cell nests were surrounded by supportive stromal and immune cells. The adrenergic tumor cell composition observed in TH-MYCN tumors is highly reminiscent of human NB. Interestingly, we discovered a cluster of immature adrenergic tumor cells aligning with normal fetal cells transitioning from bridge to chromaffin state (characterized by Sox11, Atrx, Xist, Ptprs, Tcf4). Distinct genomic aberrations, particularly unique chromosomal deletions, were found in the immature adrenergic tumor cells relative to their sympathoblast and chromaffin tumor cell counterparts. Conclusions: Examining the cellular composition of TH-MYCN tumors at a transcriptional level gives a detailed view of tumor cell heterogeneity at an unprecedented resolution. This comprehensive atlas of TH-MYCN tumors provides a resource for unmasking novel therapeutic targets. Citation Format: Bethel Tesfai Embaie, Adele Alchahin, Thale Kristin Olsen, Hirak Sarkar, Shenglin Mei, Ninib Baryawno. Single-cell landscape of the TH-MYCN neuroblastoma mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1678.

Mesenchymal-Type Neuroblastoma Cells Escape ALK Inhibitors.

Cancer therapy frequently fails due to the emergence of resistance. Many tumors include phenotypically immature tumor cells, which have been implicated in therapy resistance. Neuroblastoma cells can adopt a lineage-committed adrenergic (ADRN) or an immature mesenchymal (MES) state. They differ in epigenetic landscape and transcription factors, and MES cells are more resistant to chemotherapy. Here we analyzed the response of MES cells to targeted drugs. Activating anaplastic lymphoma kinase (ALK) mutations are frequently found in neuroblastoma and ALK inhibitors (ALKi) are in clinical trials. ALKi treatment of ADRN neuroblastoma cells with a tumor-driving ALK mutation induced cell death. Conversely, MES cells did not express either mutant or wild-type ALK and were resistant to ALKi, and MES cells formed tumors that progressed under ALKi therapy. In assessing the role of MES cells in relapse development, TRAIL was identified to specifically induce apoptosis in MES cells and to suppress MES tumor growth. Addition of TRAIL to ALKi treatment of neuroblastoma xenografts delayed relapses in a subset of the animals, suggesting a role for MES cells in relapse formation. While ADRN cells resembled normal embryonal neuroblasts, MES cells resembled immature precursor cells, which also lacked ALK expression. Resistance to targeted drugs can therefore be an intrinsic property of immature cancer cells based on their resemblance to developmental precursors. SIGNIFICANCE: In neuroblastoma, mesenchymal tumor cells lack expression of the tumor-driving ALK oncogene and are resistant to ALKi, but dual treatment with ALKi and mesenchymal cell-targeting TRAIL delays tumor relapse.

CSIG-17. PRMT5 INHIBITION SENSITIZES GLIOBLASTOMA MODELS TO TRAMETINIB TREATMENT

Abstract INTRODUCTION Glioblastoma (GBM) is the most common malignant primary brain tumor. With limited effective therapeutic strategies, prognosis for GBM is very poor. Our previous study shows that the expression of Protein Arginine Methyltransferase 5 (PRMT5) is upregulated in GBM; its inhibition promotes anti-GBM effect through apoptosis and senescence of mature and immature tumor cells, respectively. In GBM, RAS-RAF- MEK-ERK signaling is aberrantly activated and promotes tumor growth. Therefore, MEK inhibitors, including trametinib are currently under investigation for GBM therapy. In this study, we tested whether inhibition of PRMT5 can enhance the anti-tumor efficacy of trametinib in GBM. METHODS Patient-derived primary GBM neurospheres (GBMNS) with transient PRMT5 knockdown were treated with trametinib and cell viability, proliferation, cell cycle progression, and western blot analysis were conducted. In vivo, PRMT5-intact and -depleted GBMNS were intracranially implanted in NSG mice and treated with trametinib by daily oral gavage, and tumor progression and mice survival rate were analyzed by MRI and Kaplan-Meier survival curve, respectively. RESULTS Trametinib treatment upregulated the expression of PRMT5 in GBMNS. Depletion of PRMT5 increased the cytotoxic effect of trametinib in GBMNS. In concurrence with the trametinib-induced PRMT5 upregulation, trametinib treatment increased the activity of AKT that was blocked with PRMT5 knockdown. In vivo, PRMT5-depletion extended the survival of the tumor bearing mice that further increased in combination with trametinib treatment. Interestingly, trametinib treatment alone had no survival benefit. CONCLUSION Trametinib treatment induces PRMT5 expression. Depletion of trametinib-induced PRMT5 expression sensitizes GBMNS for trametinib by inhibiting AKT activity.

STEM-23. INHIBITING PROTEIN PHOSPHATASE 2A INCREASES THE ANTITUMOR EFFECT OF PROTEIN ARGININE METHYLTRANSFERASE 5 INHIBITION IN MODELS OF GLIOBLASTOMA

Abstract BACKGROUND: Despite multi-model therapy of maximal surgical resection, radiation, chemotherapy, and tumor treating fields, median survival of Glioblastoma (GBM) patients is less than two years. Protein Arginine Methyltransferase 5 (PRMT5) catalyzes the symmetric di-methylation of arginine residues and is overexpressed in GBM. Inhibition of PRMT5 causes senescence of immature GBM tumor cells. LB100, first-in-class small molecule inhibitor of Protein Phosphatase 2A (PP2A) can sensitize therapy-resistant tumor cells. Here, we tested the anti-GBM effect of concurrent PRMT5 and PP2A inhibition. Methods: Patient-derived primary GBM neurospheres (GBMNS), transfected with PRMT5 target-specific siRNA were treated with LB100 and subjected to in vitro assays including PP2A activity and western blot. The intracranial mouse xenograft model was used to test the in vivo antitumor efficacy of combination treatment. Results: We found that PRMT5-depletion increased PP2A activity in GBMNS. LB100 treatment significantly reduced the viability of PRMT5-depleted GBMNS compared to PRMT5 intact GBMNS. LB100 enhanced the G1 cell cycle arrest induced by PRMT5-depletion. Combination therapy also increased the expression of phospho-MLKL. Necrostatin-1 rescued PRMT5-depleted cells from the cytotoxic effects of LB100, indicating that necroptosis caused the enhanced cytotoxicity of combination therapy. In the in vivo mouse tumor xenograft model, LB100 treatment combined with transient depletion of PRMT5 significantly decreased tumor size and prolonged mice survival, while LB100 treatment alone had no survival benefit. Conclusion: Overall, combined PRMT5 and PP2A inhibition had significantly greater antitumor effects than PRMT5 inhibition alone.

STEM-16. DUAL INHIBITION OF PROTEIN ARGININE METHYLTRANSFERASE 5 AND PROTEIN PHOSPHATASE 2A ENHANCES THE ANTI-TUMOR EFFICACY IN PRIMARY GLIOBLASTOMA NEUROSPHERES

Abstract INTRODUCTION Glioblastoma (GBM) is the most common malignant primary brain tumor and has a heterogeneous tumor cell population. The median survival of GBM patients is less than two years with current multi-model therapy of maximal surgical resection followed by chemotherapy, radiation and tumor treating fields. Protein Arginine Methyltransferase 5 (PRMT5) regulates cellular functions through symmetric di-methylation of arginine residues of histone and non-histone proteins. Our recent findings show that PRMT5 is overexpressed in GBM; its inhibition causes apoptosis and senescence of mature and immature GBM tumor cells respectively. Protein Phosphatase 2A (PP2A), a serine-threonine phosphatase, is associated with senescent tumor cells that contribute to therapy resistance; LB100 is a first-in-class small molecule inhibitor of PP2A that can sensitize tumor cells that are chemo- and radiation-therapy resistant. In this study, using patient-derived primary GBM neurospheres (GBMNS), we tested the anti-GBM effect of concurrent PRMT5 and PP2A inhibition. METHODS Patient-derived primary GBM neurospheres transfected with PRMT5 target-specific siRNA were treated with LB100 and subjected to in vitro assays such as proliferation assay, cell cycle analysis, cytotoxicity assay, PP2A activity and western blot. RESULTS LB100 treatment significantly reduced the viability of PRMT5-depleted GBM cells as compared to PRMT5 intact cells. LB100 caused G1 cell cycle arrest through inactivation of Rb protein; this effect is further enhanced in combination with PRMT5-depletion. Combination therapy also increased the expression of phospho-MLKL; Necrostatin-1 rescued PRMT5-depleted cells from the cytotoxic effects of LB100 indicating that necroptosis caused the enhanced cytotoxicity in combination therapy. We also found that PRMT5-depletion increased the PP2A activity in GBM neurospheres. CONCLUSION Combining the PRMT5 inhibition and PP2A inhibition produced greater antitumor effects than with PRMT5 inhibition alone.

Abstract SY24-02: Neuroblastoma: A developmental twist

Abstract Intra-tumor heterogeneity is considered as a source of drug-resistant cells that can escape therapy and form relapses. Several tumor types display a structured intra-tumor heterogeneity, consisting of immature tumor cells and lineage-committed tumor cells. The immature populations of some tumor types have been implicated in drug resistance. The pediatric tumor neuroblastoma includes besides lineage committed adrenergic (ADRN) cells a minority of undifferentiated mesenchymal (MES) tumor cells which diverge in gene expression and epigenetic modifications (van Groningen et al., Nature Genetics 2017). MES cells are relatively resistant to chemotherapy and are enriched in post-treatment samples, suggesting selection and a role in relapse development. However, the co-existence of two tumor cell populations, their differential drug sensitivity and their relation to normal development remain enigmatic. Here we show how MES-type neuroblastoma cells fundamentally differ from ADRN-type cells and resemble normal precursor cells of the adrenergic lineage, including expression of metabolic routes providing resistance to therapy. MES cells and ADRN cells share the same genetic defects, but strongly differ in super enhancers. Each cell type is marked by about 200 specific super enhancers that are absent in the other cell type. Analysis of the genes under their control identified about 20 MES-specific transcription factors and 20 ADRN-specific transcription factors. Chip-seq analysis showed that they conform to a model of MES-specific or ADRN-specific core regulatory circuitries (CRC). Such circuitries were proposed to form a feed-forward system that imposes lineage specification (Hnisz et al., Cell 2012). In agreement with a cell-type specifying role for the CRC, we found that induced expression of MES-specific CRC transcription factors could reprogram ADRN-type cells into MES-type cells. This included a shift towards MES-type super enhancers and expression of associated MES-type genes. Neuroblastoma are tumors of the peripheral adrenergic lineage, which is neural crest derived. MES-type cells lack expression of typical differentiation markers of this lineage, like enzymes for the adrenalin synthesis route TH and DBH. We therefore analyzed whether MES cells resemble precursor cell types of this lineage. Schwann Cell Precursors (SCP) were recently implicated as migratory precursor cells of the adrenergic lineage (Furlan et al., Science 2017). We found that MES cells are highly similar to SCP cells. We therefore analyzed whether the drug resistance of MES cells relate to their normal developmental counterparts. Indeed we observed that the similarity of SCP and MES cells extends to metabolic routes that affect resistance to drugs used in neuroblastoma therapy. Our analyses show that heterogeneity in neuroblastoma is structured and resembles cell types of the normal differentiation program of the adrenergic lineage. MES and ADRN cell types have conserved gene expression programs that determine their response to therapy. MES cells are thereby unresponsive to clinically used therapeutic drugs and may survive therapy. Targeting of lineage-differentiated as well as immature tumor cell types may therefore be a promising strategy to attenuate development of therapy-resistant tumor relapses. Citation Format: Rogier Versteeg, Linda Valentijn, Jan Koster, Tim van Groningen, Mohamed Hamdi, Ellen Westerhout, Johan van Nes. Neuroblastoma: A developmental twist [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr SY24-02.

Shift of microRNA profile upon orthotopic xenografting of glioblastoma spheroid cultures.

Glioblastomas always recur despite surgery, radiotherapy and chemotherapy. A key player in the therapeutic resistance may be immature tumor cells with stem-like properties (TSCs) escaping conventional treatment. A group of promising molecular targets are microRNAs (miRs). miRs are small non-coding RNAs exerting post-transcriptional regulation of gene expression. In this study we aimed to identify over-expressed TSC-related miRs potentially amenable for therapeutic targeting. We used non-differentiated glioblastoma spheroid cultures (GSCs) containing TSCs and compared these to xenografts using a NanoString nCounter platform. This revealed 19 over-expressed miRs in the non-differentiated GSCs. Additionally, non-differentiated GSCs were compared to neural stem cells (NSCs) using a microarray platform. This revealed four significantly over-expressed miRs in the non-differentiated GSCs in comparison to the NSCs. The three most over-expressed miRs in the non-differentiated GSCs compared to xenografts were miR-126, -137 and -128. KEGG pathway analysis suggested the main biological function of these over-expressed miRs to be cell-cycle arrest and diminished proliferation. To functionally validate the profiling results suggesting association of these miRs with stem-like properties, experimental over-expression of miR-128 was performed. A consecutive limiting dilution assay confirmed a significantly elevated spheroid formation in the miR-128 over-expressing cells. This may provide potential therapeutic targets for anti-miRs to identify novel treatment options for GBM patients.

Post-bone-marrow-transplant leukemia cutis

Granulocytic sarcoma or chloroma is a tumor of immature cells from the granulocyte line that is generally associated with acute myeloid leukemia. The skin is one of the most affected organs. This lesion may complicate hematological dyscrasias, which is generally indicative of a poor prognosis. We present a case of a 51-year-old patient who was diagnosed with acute myeloid leukemia with a complex karyotype that debuted with a post-transplant cutaneous and hematological relapse, a very rare occurrence in the literature given that no extramedullary involvement was present prior to the transplant.

Fibroblast Growth Factor-2 Is an Important Factor that Maintains Cellular Immaturity and Contributes to Aggressiveness of Osteosarcoma

Osteosarcoma is the most frequent, nonhematopoietic, primary malignant tumor of bone. Histopathologically, osteosarcoma is characterized by complex mixtures of different cell types with bone formation. The role of environmental factors in the formation of such a complicated tissue structure as osteosarcoma remains to be elucidated. Here, a newly established murine osteosarcoma model was used to clarify the roles of environmental factors such as fibroblast growth factor-2 (Fgf2) or leukemia-inhibitory factor (Lif) in the maintenance of osteosarcoma cells in an immature state. These factors were highly expressed in tumor environmental stromal cells, rather than in osteosarcoma cells, and they potently suppressed osteogenic differentiation of osteosarcoma cells in vitro and in vivo. Further investigation revealed that the hyperactivation of extracellular signal-regulated kinase (Erk)1/2 induced by these factors affected in the process of osteosarcoma differentiation. In addition, Fgf2 enhanced both proliferation and migratory activity of osteosarcoma cells and modulated the sensitivity of cells to an anticancer drug. The results of the present study suggest that the histology of osteosarcoma tumors which consist of immature tumor cells and pathologic bone formations could be generated dependent on the distribution of such environmental factors. The combined blockade of the signaling pathways of several growth factors, including Fgf2, might be useful in controlling the aggressiveness of osteosarcoma.

Spontaneous Nephroblastoma in a Japanese Giant Salamander (<i>Andrias japonicus</i>)

An adult male Japanese giant salamander (Andrias japonicus) died accidentally, and necropsy showed a white mass (23 × 15 mm) in the left kidney and hepatorrhexis with hemoperitoneum. Histologically, the renal mass was mainly composed of immature nephroblastic tumor cells. In the tumor tissue, a trabecular pattern lined by oval to polygonal tumor cells with a rich interstitium, solid growth and a few tubular structures was observed. Nephroblastic tumor cells were strongly positive for vimentin and weakly positive, and epithelium-like tumor cells were strongly positive for cytokeratin. However, antibody for Wilms' tumor protein 1 did not react with the salamander's cells. On electron microscopy, a desmosome junction was observed between tumor cells. This is the first report of nephroblastoma in a Japanese giant salamander.

Abstract 914: The role of CD44 variant in the development of spasmolytic polypeptide-expressing metaplasia (SPEM) and gastric cancer

Abstract CD44 is a marker of tumor-initiating cells in gastric cancer. However, the cause or consequence of elevated CD44 in such immature tumor cells is not known. Gastric carcinogenesis involves a transition from normal mucosa to gastritis, which then leads to metaplasia and eventually adenocarcinoma. Although the emergence of metaplasia or dysplasia is a key event of inflammation-related gastric carcinogenesis, the precise mechanism underlying the transition from normal gastric epithelium to metaplasia and cancer remains unsolved. Spasmolytic polypeptide (known as trefoil factor family 2)-expressing metaplasia (SPEM) results from a metaplastic change of gastric epithelial cells in response to chronic inflammation. Here we show that the trefoil factor family 2 (TFF2)+ metaplastic glands as well as gastric tumor glands contain CD44 variant isoform-expressing (CD44v+) cells in K19-Wnt1/C2mE mouse, a genetic mouse model for gastric tumorigenesis. Furthermore, the analysis of three transgenic mouse lines K19-Wnt1, K19-C2mE and K19-Wnt1/C2mE revealed that de novo expression of CD44v in SPEM cells is triggered by prostaglandin E2-mediated signaling. Isolated CD44-expressing tumor cells in K19-Wnt1/C2mE mice by fluorescence-activated cell sorting (FACS) manifested increased expression of SPEM-related genes, suggesting that metaplastic epithelium might give rise to both of CD44v+ tumor cells and CD44v+ SPEM cells in mice. To investigate the role of CD44 in the development of SPEM and gastric tumor in mice, we generated CD44-/- K19-Wnt1/C2mE mice. We found that CD44 ablation significantly suppresses the development of SPEM and gastric tumor, suggesting that CD44v+ cells play a key role in gastric tumorigenesis. Furthermore, we found that the emergence of CD44v+ SPEM glands adjacent to cancer is tightly associated with the CD44v-expressing gastric cancer formation in human. Our present study thus suggest that SPEM cells might be susceptible for oncogenesis due to their proliferative capacity and that CD44v+ SPEM cells are cells-of-origin for CD44v+ tumor-initiating cells in human gastric adenocarcinoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 914. doi:10.1158/1538-7445.AM2011-914

Undifferentiated sarcoma of the maxillary sinus: Report of a rare case in an adult

A 51-year-old man complained of left facial swelling and recurrent nasal bleeding. A giant solid tumor in the left maxillary sinus was detected on head CT and MRI, and this tumor was destroying the maxilla and extending into the orbit, pterygoid muscle and posterior paranasal sinuses. The resected specimen consisted of spindle cells containing necrotic material. Histological examination revealed immature tumor cells, and immunohistological study of the tumor showed staining was only positive for vimentin. We accordingly diagnosed undifferentiated sarcoma in the maxillary sinus. Combination chemotherapy with vincristine, doxorubicin, cyclophosphamide/ifosfamide with mesna and etoposide was administered; however, the tumor was unresponsive and the patient died after around 3 months.

Unusual survival of an adult with pleuropulmonary blastoma and neurofibromatosis

Clinical Summary Chest radiography showed a solid mass encased within a large cystic structure, suspicious for aspergilloma of the left lung. A chest computed tomographic scan revealed a huge multiseptated cystic structure involving the entire major fissure of the left lung, containing a multilobulated soft tissue mass (Figure 1), and measuring approximately 10 20 cm. The mass and cysts were completely excised through a left thoracotomy. The specimen weighed 85 g in aggregate and consisted of thin-walled cysts, imparting a botryoid (ie, grape-like) appearance, with minor solid components (Figure 2, A ). Microscopically, small immature tumor cells with ovoid to spindle-shaped nuclei were set in a myxoid stroma. Cellularity was highest in the so-called cambium layer just beneath the attenuated cyst lining (Figure 2, B). Tumor cells were positive for desmin and other muscle markers by immunohistochemistry. A diagnosis of pleuropulmonary blastoma (PPB) type II was made. The patient’s postoperative course was uneventful. Retrospective pathologic examination of the blebectomy specimen obtained 2 years earlier revealed subtle histologic features suggestive of PPB type I. The patient received a multidrug regimen of 11 cycles of chemotherapy, consisting of vincristine, actinomycin, and cyclophosphamide during the first phase, and doxorubicin (Adriamycin; Bedford Laboratories, Bedford, Ohio), cisplatin, and doxorubicin during the second phase. Follow-up computed tomography scans of the chest, abdomen, and pelvis revealed no evidence of recurrence or metastasis at 24 months. The patient is currently asymptomatic with good weight gain and normal physical strength. Discussion This case report demonstrates the cardinal clinical and pathologic features of PPB, a highly aggressive childhood malignancy, in an adult. These tumors present almost exclusively in the first decade of life. 1 To our knowledge, 4 adult patients have been reported in the literature, with only 1 survivor at 29 months, after radiation therapy of a nonresectable PPB. 2 It is now recognized that 25% of PPB cases occur in a familial setting with other tumors of childhood, such as cystic nephroma, rhabdomyosarcoma, and synovial sarcoma. 3 There are no reports in the literature of any case of PPB associated with neurofibromatosis. Clinical presentation of these rare tumors may vary from ruptured lung blebs, as in our patient, or space-occupying masses resembling a mediastinal teratoma 4 to more subtle manifestations of chest pathology or systemic disease. The clinical and radiographic differential diagnosis includes fungal lesions, congenital cystic adenomatoid malformation, bronchogenic cyst, and postinfectious pneumatocele. Three pathologic types of PPB have been described: Type I is purely cystic and may present as a congenital lung cyst; type II is a combined cystic and solid tumor; and type III is solid and can be accompanied by hemorrhage and necrosis. 2

Expression of Tissue Factor and Tissue Factor Pathway Inhibitor in situ in Laryngeal Carcinoma

The blood coagulation mechanism may support tumor progression by several mechanisms including promotion of cell proliferation and angiogenesis. Immunohistochemical procedures were applied to AMeX-fixed sections of twelve cases of squamous cell carcinoma of the larynx obtained at surgical resection to determine the presence and distribution of tissue factor (TF), tissue factor pathway inhibitor (TFPI), other coagulation factors, fibrinogen, and fibrin in situ. TF antigen was present in normal squamous epithelial cells and tumor cells, predominantly in immature tumor cells in the vicinity of the host-tumor interface. Tumor cells stained also for factors VII and X. Staining for TFPI antigen was demonstrated in the connective tissue stroma adjacent to the tumor, in microvascular endothelial cells, and in normal squamous epithelial cells. Fibrinogen and factor XIIIa were distributed throughout the tumor connective tissue stroma. Fibrin (thrombin-cleaved fibrinogen) was detected at the host-tumor interface and along the margins of tumor nodules. Tumor cells in carcinoma of the larynx express a functional, TF-initiated pathway of blood coagulation. Interpretation of these findings together with the results of clinical trials of inhibitors of TF-induced coagulation activation versus effects of inhibitors of TF expression suggest novel approaches to the experimental therapy of laryngeal carcinoma.

Interleukin-6 Gene Expression in Multiple Myeloma: A Characteristic of Immature Tumor Cells

AbstractInterleukin-6 (IL-6) has been suggested to play a major role in multiple myeloma. To investigate the source and target cells of IL-6 activity in multiple myeloma, expression of the cytokine and its receptor genes by myeloma plasma cells was studied. Tumor cells were sorted from bone marrow aspirates of myeloma patients using 4-parameter gating. Myeloma cells were identified as CD38high CD45negative-intermediate and by their light-scatter characteristics. Sorted cells contained only myeloma plasma cells. No contaminating cells were present as determined morphologically, by monoclonal cytoplasmic Ig analysis, and by polymerase chain reaction (PCR) amplification of marker genes. Myeloma cells from 45% of patients expressed IL-6; IL-6 receptor transcripts were found in 68% of the specimens. IL-6 gene expression correlated with expression of the IL-6 receptor gene (P < .005). Correlations observed between the expression of CD45, a protein tyrosine phosphatase expressed by B lymphocytes but not by plasma cells, and the expression of the IL-6 and IL-6-receptor genes (P < .0002 and P < .005, respectively) suggest that an autocrine IL-6 loop is functioning in myeloma in preplasma cells.

Interleukin-6 gene expression in multiple myeloma: a characteristic of immature tumor cells

Interleukin-6 (IL-6) has been suggested to play a major role in multiple myeloma. To investigate the source and target cells of IL-6 activity in multiple myeloma, expression of the cytokine and its receptor genes by myeloma plasma cells was studied. Tumor cells were sorted from bone marrow aspirates of myeloma patients using 4-parameter gating. Myeloma cells were identified as CD38high CD45negative- intermediate and by their light-scatter characteristics. Sorted cells contained only myeloma plasma cells. No contaminating cells were present as determined morphologically, by monoclonal cytoplasmic Ig analysis, and by polymerase chain reaction (PCR) amplification of marker genes. Myeloma cells from 45% of patients expressed IL-6. IL-6 receptor transcripts were found in 68% of the specimens. IL-6 gene expression correlated with expression of the IL-6 receptor gene (P &lt; .005). Correlations observed between the expression of CD45, a protein tyrosine phosphatase expressed by B lymphocytes but not by plasma cells, and the expression of the IL-6 and IL-6-receptor genes (P &lt; .0002 and P &lt; .005, respectively) suggest that an autocrine IL-6 loop is functioning in myeloma in preplasma cells.

A CASE REPORT OF UNDIFFERENTIATED (EMBRYONAL) SARCOMA OF THE LIVER

Undifferentiated sarcomas of the liver are very rare and have poor response to chemotherapy and radiation, with resultant poor prognosis. A case of undifferentiated sarcoma of the liver is reported. A 11-year-old woman complained of right hypochondial pain. A giant cystic tumor of the right lobe of the liver was detected by abdominal ultrasonography and CT, and this tumor was hypovascular by angiography. The resected specimen was surrounded by dense materials, with inside including necrotic materials, and no evidense of the tumor. But histological examination revealed immature tumor cells, so we diagnosed it as undifferentiated sarcoma of the liver. Postoperatively combination chemotherapy of VCR, ACD and CPA was performed, and the patient is disease free for 1 year and 5 months after surgery.

Effect of cytidine analogs on cell growth and differentiation on a human neuroblastoma line

The cytidine analog 5-AZA-2'-deoxycytidine (5-AZA-CdR) has been demonstrated to induce cellular differentiation; on the other hand, induction of differentiation has been suggested as a possible form of therapy for leukemic cells. We have evaluated the possibility that the neuroblastoma malignant tumor growth could be controlled by treatment that promotes the differentiation of immature tumor cells. We have previously reported on differentiation of murine neuroblastoma cells (41A3) treated with 5-AZA-CdR. In this paper, we describe the effect of 5-AZA-CdR on human neuroblastoma cell line CHP-100. The drug-treated cells show some degree of differentiation, demonstrated by morphological and biochemical markers. A significant DNA hypomethylation and partial inhibition of DNA synthesis and cell proliferation is also observed. This effect is more stable than that caused by another cytidine analog, Cytosine-beta-D-Arabinofuranoside (ARA-C).

Rippled‐pattern trichomatricoma

A hair matrix tumor showing an unusual tumor cell arrangement was found at the base of a solitary trichoepithelioma. Coexisting with solid epithelial islands and immature hair follicle-like stroma resembling the Verocay bodies of neurilemmoma or "ripplemarks" on waves were found. In other areas myxomatous degeneration of the stroma changed the rippling into a cribriform pattern. In some parts of the tumor there was a dense melanin pigment associated with MEL5 stained melanocytes. S-100 and CD1 (OKT6) antigen stains demonstrated Langerhans cells scattered in the parenchyma and less frequently in the stroma. The majority of tumor cells were considered immature pilar cortical cells because of the following: 1. HKN-6 was strongly positive; 2. a large number of melanocytes were associated with tumor cells in some foci; 3. ultrastructurally immature tumor cells, which had electron-dense tonofilaments and many desmosomes, were transformed without production of trichohyalin granules into semikeratinized cells which showed nuclear degeneration and loss of electron density in tonofilaments. This tumor, however, has not attained the degree of differentiation observed in trichoblastoma (1) another example of an immature cortical cell tumor. Squamous eddy-like or horn pearl-like foci of incomplete keratinization and large keratin-filled cysts were also present within the immature parenchyma, indicating that some immature cells were differentiating toward non-cortical cells, as found in the outer sheath. We would like to designate this tumor "rippled pattern trichomatricoma", a new entity.