Acute myeloid leukemia arising from a donor derived premalignant hematopoietic clone: A possible mechanism for the origin of leukemia in donor cells

AbstractDuring recent years, it has become increasingly evident that donor leukemia following allogeneic transplant may be more common then realized in the past. We identified five cases of potential donor leukemia cases during past five years. The precise mechanism of the origin of such leukemias, however, remains poorly defined. In this short communication, we report a well documented case of donor-derived de novo acute myeloid leukemia (AML) that developed fourteen years after allogeneic stem cell transplantation for treatment induced AML for his primary malignancy Immunoblastic lymphoma. This case allows us to postulate a possible mechanism of the origin of donor leukemia. The de novo AML clone contained a distinct cytogenetic abnormality, trisomy 11, which was simultaneously detected in preserved peripheral blood obtained at the time of transplantation as well as in the current bone marrow from an otherwise clinically and phenotypically normal donor. The findings from this unique case, provides insight into the process of leukemogenesis, and suggests that the sequence of events leading to leukemogenesis in this patient involved the senescence/apoptosis of normal donor hematopoietic cells due to telomere shortening resulting in the selective proliferation and transformation of this clone with MLL (mixed-lineage leukemia) gene amplification

The Society for Immunotherapy of Cancer statement on best practices for multiplex immunohistochemistry (IHC) and immunofluorescence (IF) staining and validation.

OBJECTIVES: The interaction between the immune system and tumor cells is an important feature for the prognosis and treatment of cancer. Multiplex immunohistochemistry (mIHC) and multiplex immunofluorescence (mIF) analyses are emerging technologies that can be used to help quantify immune cell subsets, their functional state, and their spatial arrangement within the tumor microenvironment. METHODS: The Society for Immunotherapy of Cancer (SITC) convened a task force of pathologists and laboratory leaders from academic centers as well as experts from pharmaceutical and diagnostic companies to develop best practice guidelines for the optimization and validation of mIHC/mIF assays across platforms. RESULTS: Representative outputs and the advantages and disadvantages of mIHC/mIF approaches, such as multiplexed chromogenic IHC, multiplexed immunohistochemical consecutive staining on single slide, mIF (including multispectral approaches), tissue-based mass spectrometry, and digital spatial profiling are discussed. CONCLUSIONS: mIHC/mIF technologies are becoming standard tools for biomarker studies and are likely to enter routine clinical practice in the near future. Careful assay optimization and validation will help ensure outputs are robust and comparable across laboratories as well as potentially across mIHC/mIF platforms. Quantitative image analysis of mIHC/mIF output and data management considerations will be addressed in a complementary manuscript from this task force

Myeloid ELF1-like factor is a potent activator of interleukin-8 expression in hematopoietic cells

Myeloid ELF1-like factor (MEF), also known as ELF4, is a member of the ETS family of transcription factors which is expressed in hematopoietic cells. MEF-deficient mice have defects in natural killer cell and natural killer T cell development, suggesting a role for MEF in regulating innate immunity. MEF also functions in myeloid cells, where it can transactivate target genes. To identify MEF target genes in a "myeloid" environment, we created an inducible expression system and used oligonucleotide microarrays to examine the transcript profile of HEL cells after induction of MEF expression. Sixteen genes were reproducibly turned on or off more than 2-fold, 8 h after induction of MEF expression, and we examined one of the genes, interleukin-8 (IL-8), in greater detail. IL-8 is a CXC chemokine involved in neutrophil chemoattraction, angiogenesis, and stem cell mobilization. It is expressed by several tumor types, and its expression is regulated primarily transcriptionally. The IL-8 promoter contains three ETS binding sites, and we identified the specific site that binds MEF and is required for MEF responsiveness. MEF, but not the closely related ETS factors PEA3, ETS1, ETS2, ELF1, or PU.1, strongly activates the IL-8 promoter. MEF overexpression is sufficient to induce IL-8 protein expression, and reduction in MEF expression (using RNA interference) results in decreased IL-8 levels. These data demonstrates that MEF is an important regulator of IL-8 expression

Patterns of expression of cell cycle/apoptosis genes along the spectrum of thyroid carcinoma progression

Genetic screening studies suggest that genetic changes underlie progression from well differentiated to anaplastic thyroid cancers. The aim of this study is to determine to what extent cell cycle/apoptosis regulators contribute to cancer progression. Tissue microarrarys (TMAs) were constructed from well-differentiated papillary thyroid carcinoma (WDPTC; n = 41), poorly differentiated thyroid carcinoma (PDTC; n = 43), and anaplastic thyroid carcinoma (ATC; n = 22). TMAs were immunostained for 7 different cell cycle/apoptosis-related genes (p53, Ki-67, bcl-2, mdm-2, cyclin D1, p21, and p27). p53 (0%, 12%, 32%) and Ki-67 (5%, 49%, 82%) were expressed with increasing frequency, and bcl-2 (68%, 42%, 0%) and p21 (40%, 7%, 0%) with decreasing frequency in WDPTC to PDTC and ATC, respectively (P < .001). Interestingly, mdm-2 (54%, 5%, 0%) showed decreased expression along the progression axis (P < .001). p27 and cyclin D1 were expressed in <15% of cases, with a trend toward decreasing expression from WDPTC to PDTC to ATC. These data confirm the presence of increasing genetic complexity with progressive dedifferentiation in thyroid cancer, with aberrant tumor suppressor activity and increased proliferative activity being most prevalent in ATC. The data also confirm the intermediate position of PDTC in the classification scheme of thyroid carcinoma

The ETS Protein MEF Is Regulated by Phosphorylation-Dependent Proteolysis via the Protein-Ubiquitin Ligase SCF(Skp2)

MEF is an ETS-related transcription factor with strong transcriptional activating activity that affects hematopoietic stem cell behavior and is required for normal NK cell and NK T-cell development. The MEF (also known as ELF4) gene is repressed by several leukemia-associated fusion transcription factor proteins (PML-retinoic acid receptor α and AML1-ETO), but it is also activated by retroviral insertion in several cancer models. We have previously shown that cyclin A-dependent phosphorylation of MEF largely restricts its activity to the G(1) phase of the cell cycle; we now show that MEF is a short-lived protein whose expression level also peaks during late G(1) phase. Mutagenesis studies show that the rapid turnover of MEF in S phase is dependent on the specific phosphorylation of threonine 643 and serine 648 at the C terminus of MEF by cdk2 and on the Skp1/Cul1/F-box (SCF) E3 ubiquitin ligase complex SCF(Skp2), which targets MEF for ubiquitination and proteolysis. Overexpression of MEF drives cells through the G(1)/S transition, thereby promoting cell proliferation. The tight regulation of MEF levels during the cell cycle contributes to its effects on regulating cell cycle entry and cell proliferation

New Technologies to Image Tumors.

The premise of this book is the importance of the tumor microenvironment (TME). Until recently, most research on and clinical attention to cancer biology, diagnosis, and prognosis were focused on the malignant (or premalignant) cellular compartment that could be readily appreciated using standard morphology-based imaging