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.

Association of quantitative assessment of the intrafollicular proliferation index with outcome in follicular lymphoma.

The role of the proliferation index (PI) as an outcome predictor in follicular lymphoma (FL) isn't clear. We have previously demonstrated that quantitative image analysis (QIA) is a robust tool for PI determination and the present study aimed to determine the significance of the PI for outcome in low-grade FL. One hundred and twenty-nine patients with grade 1-2 FL were retrospectively analysed. Slides were scanned digitally and follicle/tumour-involved areas were annotated. The intrafollicular PI was estimated by analysing a median of 10 follicles per case. Patients were divided into two groups: PI < 30%, PI ≥ 30% and clinical outcome was analysed. Among the 129 patients analysed, intrafollicular PI ranged from 0·6 to 63·2% with a median of 23·3%. Overall survival was not influenced by PI group. Among those patients initially observed, intrafollicular PI < 30% was associated with longer time to first therapy compared to patients with a PI ≥ 30%. In the group of patients that were treated at diagnosis, PI was not predictive of time to treatment failure (TTTF). Intrafollicular PI is an important predicator of TTFT for patients who are candidates for observation. Further confirmation in an independent cohort of patients is necessary to determine the clinical validity of the results.

Regulatory T cell infiltration predicts outcome following resection of colorectal cancer liver metastases.

BACKGROUND: Tumor-infiltrating lymphocyte (TIL) counts in colorectal cancer liver metastases (CRCLM) predict survival following resection. While CD4 and CD8 T cells have been correlated with outcome following CRCLM resection, the role of regulatory T cells (Treg) is not well defined. METHODS: TIL in 188 patients who underwent CRCLM resection between 1998 and 2000 were analyzed by immunohistochemistry using tissue microarrays. Correlation between TIL composition and outcome was determined while controlling for established prognostic factors. Total T cells (CD3), helper T cells (CD4), cytotoxic T cells (CD8), and Treg (FoxP3) were analyzed. RESULTS: Median follow-up time was 40 months for all patients and 95 months for survivors. Overall survival (OS) at 5 and 10 years was 40 and 25%, respectively. The CD4 T cell count correlated with OS (p = .02) and recurrence-free survival (p = .04). A high number of CD8 T cells relative to total T cells (CD8:CD3 ratio) predicted longer OS times (p = .05). Analysis of Treg revealed that high FoxP3:CD4 (p = .03) and FoxP3:CD8 (p = .05) ratios were independent predictors of shorter OS. Patients with a high clinical risk score (CRS) were more likely to have a high number of intratumoral Treg, and patients ≥65 years old had a less robust CRCLM T cell infiltration. CONCLUSIONS: A high number of Treg relative to CD4 or CD8 T cells predicted poor outcome, suggesting an immunosuppressive role for FoxP3 + TIL. The intratumoral immune response was an independent predictor of outcome in patients with colorectal liver metastases.

Ddx18 is essential for cell-cycle progression in zebrafish hematopoietic cells and is mutated in human AML.

In a zebrafish mutagenesis screen to identify genes essential for myelopoiesis, we identified an insertional allele hi1727, which disrupts the gene encoding RNA helicase dead-box 18 (Ddx18). Homozygous Ddx18 mutant embryos exhibit a profound loss of myeloid and erythroid cells along with cardiovascular abnormalities and reduced size. These mutants also display prominent apoptosis and a G1 cell-cycle arrest. Loss of p53, but not Bcl-xl overexpression, rescues myeloid cells to normal levels, suggesting that the hematopoietic defect is because of p53-dependent G1 cell-cycle arrest. We then sequenced primary samples from 262 patients with myeloid malignancies because genes essential for myelopoiesis are often mutated in human leukemias. We identified 4 nonsynonymous sequence variants (NSVs) of DDX18 in acute myeloid leukemia (AML) patient samples. RNA encoding wild-type DDX18 and 3 NSVs rescued the hematopoietic defect, indicating normal DDX18 activity. RNA encoding one mutation, DDX18-E76del, was unable to rescue hematopoiesis, and resulted in reduced myeloid cell numbers in ddx18(hi1727/+) embryos, indicating this NSV likely functions as a dominant-negative allele. These studies demonstrate the use of the zebrafish as a robust in vivo system for assessing the function of genes mutated in AML, which will become increasingly important as more sequence variants are identified by next-generation resequencing technologies.

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.

The ETS protein MEF is regulated by phosphorylation-dependent proteolysis via the protein-ubiquitin ligase SCFSkp2.

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 alpha 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.

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

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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 carcinomas.

Expression of p63 in diffuse large B-cell lymphoma.

The p63 gene, a homolog of the tumor suppressor gene TP53, maps to chromosome 3q27-28, a region frequently displaying genomic amplification in squamous cell carcinomas. p63 is expressed in a variety of epithelial tissues and has been reported to be critical for the normal development of stratified epithelia, including skin epidermis. In a previous study, the authors reported the expression of p63 in occasional cells in the germinal center of lymph nodes and also observed p63 expression in B-cell lymphomas, among other tumor types surveyed in that analysis. The present study was conducted to further analyze the potential clinical significance of identifying p63 expression, assessing a larger cohort of well-characterized patients with diffuse large B-cell lymphoma (DLBCL) (n = 172 cases) and a panel of established lymphoma cell lines. p63 expression at the microanatomic detail was examined by immunohistochemistry using a monoclonal antibody (clone 4A4), while distinction of p63 isoforms was analyzed by Western blotting and reverse transcription-polymerase chain reaction using isoform-specific primers. The authors found that a subset of DLBCL (32% of cases) expressed p63 in the nuclei of neoplastic lymphocytes. Examination of the different p63 isoforms revealed that the DeltaNp63 species was expressed by only one cell line, while the other p63 isoforms were found in most cell lines analyzed. The authors also observed that p63 expression correlated with high proliferative index, as assessed by Ki-67 immunostaining. Even though in univariate analysis p63 expression did not correlate with overall survival, the association of p63 with increased proliferative index suggests its involvement in DLBCL tumor progression.