Topoisomerase 2α status in invasive breast carcinoma - comparison of its clinical value according to immunohistochemical and fluorescence in situ hybridization methods of evaluation.

The main purpose of the study was to compare topoisomerase 2α (TOP2A) status in invasive breast carcinomas to the outcome of a therapy containing neoadjuvant treatment with anthracyclines (a combination chemotherapy treatment for breast cancer, namely AC [cyclophosphamide, doxorubicin]). To achieve these goals we created a method of evaluation with criteria based on two methods used in the present study (immunohistochemical [IHC] and fluorescence in situ hybridization [FISH]). The threshold for positive immunohistochemically evaluated status was set for all cases with: nuclear stain intensity score 3+ in 10% or more nuclei and nuclear stain intensity score 2+ in 50% or more nuclei. Our results suggest that TOP2A status may be used as a predictive factor for patient selection for protocols which include anthracyclines as one of the chemotherapeutics. Both methods, IHC and FISH, are suitable for implementation for diagnostic purposes, but IHC positive status measured according to the criteria presented above is the best predictor of longer disease-free survival (DFS) according to our study. Immunohistochemical also gave satisfactory results in all analyzed cases in comparison to only 60% of cases analyzed by FISH.

Efficient generation of human T cells from a tissue-engineered thymic organoid.

Biocompatible inorganic matrices have been used to enhance bone repair by integrating with endogenous bone architecture. Hypothesizing that a three-dimensional framework might support reconstruction of other tissues as well, we assessed the capacity of a tantalum-coated carbon matrix to support reconstitution of functioning thymic tissue. We engineered a thymic organoid by seeding matrices with murine thymic stroma. Co-culture of human bone marrow-derived hematopoietic progenitor cells within this xenogeneic environment generated mature functional T cells within 14 days. The proportionate T-cell yield from this system was highly reproducible, generating over 70% CD3+ T cells from either AC133+ or CD34+ progenitor cells. Cultured T cells expressed a high level of T-cell receptor excision circles (TREC), demonstrating de novo T lymphopoiesis, and function of fully mature T cells. This system not only facilitates analysis of the T-lymphopoietic potential of progenitor cell populations; it also permits ex vivo genesis of T cells for possible applications in treatment of immunodeficiency.

Tissue source dictates lineage outcome of human fetal CD34(+)CD38(-) cells.

OBJECTIVE: The translocation from fetal liver hematopoiesis to secondary organs occurs during the second trimester of human gestation. It has been hypothesized that stem cells migrate and acquire lineage potential based on cues specific to the adopted microenvironment. We evaluated primitive hematopoietic cell populations in the fetal human to determine if lineage restriction precedes or follows translocation to sites of hematopoietic activity including thymus, spleen, bone marrow, and liver. METHODS: Sets of hematopoietic tissues from individual second-trimester human abortuses were used to compare and quantitate the lineage outcome of immunophenotypically primitive cells from each of the hematopoietic organs using ex vivo myeloid and lymphoid differentiation systems. RESULTS: Despite uniformity in immunophenotype, functional capabilities were highly restricted by the tissue of origin and alteration in the ex vivo differentiation context did not lead to a change in differentiation outcome. CONCLUSION: Translocation of primitive cells from fetal liver to tissues of mature hematopoietic activity is associated with tissue-specific, quantitative changes in differentiation potential that are unresponsive to alternative differentiation environments. These data suggest that multipotentiality is lost prior to or upon stem-cell migration in the developing human. It is not persistent with residence in a secondary hematopoietic organ.