research

  In our laboratory, we are making research with a focus on quantitave evaluation of biological characteristics including genotype and phenotype of human solid cancers. We employ three technologies; (1) molecular cytogenetics such as fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH), (2) high-throughput cell analysis methods including devices of cell array and multiplex-immunostain chip, and (3) cytometry including flow cytometry and image cytometry like laser scanning cytometry (LSC) which allows quantitative analysis of cells. Cell array system and multiplex immunostain chips have been originally developed in our laboratory as sophisticated cell analysis methods. In addition, we are developing new technologies for assisting our research.

 We are interested in genomic abnormalities of solid tumors, which are analyzed by means of molecular cytogenetic technologies such as fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH). We have already examined more than 3,000 tumors by chromosomal CGH, and now we are using array-based CGH as well as cromosomal CGH. We have identified genomic alterations (copy number aberrations) linked to biological characteristics in human solid tumors. It is indicated that CGH analysis of solid tumors provides useful information in personalized treatment of cancer.

Topics

1. We have succeeded in developing a gastric cancer specific mini-array allowing estimation of node metastasis, liver metastasis, peritoneal dissemination and depth of tumor invasion. The mini-array contains 50 BAC clones for estimating these clinicopathological parameters. This system allows a clinicopathological state even in a single biopsy specimen before surgical operation.

2. We have dicovered CNP (copy number polymorphism) closely linked with cancer susceptibility (Pat. #2008-48668). The CNP is detected in almost all patients with a specific type of cancer. CNP is different in different type of cancer.

II. The development of new technologies for analysis of cellular characteristics

 We have been developing new technologies with the aim of rapid and efficient analysis of gene expression in both individual cell and a cell population. Three representative technologies developed in this laboratory are introduced here.

(1) Cell array

A cell array device allows analysis of cellular characteristics such as DNA ploidy, numerical chromosomal aberrations, and antigen expression in multiple specimens in a single experiment. Fifty (10 x 5) spots, 2 mm in diameter, were arrayed in an area of 30 x 16 mm on a glass slide, and approximately 1,000 cells were placed on each spot. This system is powerful in image cytometry. (Am J Pathol 2000;157:723-8)

(2) Multiplex-immunostain chip

  To make immunohistochemical examination more efficient, we have developed a novel device called a "multiplex-immunostain chip (MI chip)." The chip is a panel of antibodies contained in a silicon rubber plate that consists of 50 x 2-mm-diameter wells. A tissue section slide is placed on the plate and is fastened tightly with a specially designed clamp. The plate with the slide is then turned upside down, which applies the antibodies to the section. This technology allows IHC staining of a tissue section with 50 different antibodies in a single experiment, reducing the time, work, and expense of IHC analysis. In addition, it enables pathologists to compare expression of multiple antigens on a tissue section simply by changing microscopic fields on a single slide. This device can be used in various applications in differential diagnosis of tumors and the field of cell biology. (J Histochem Cytochem. 2004; 52: 205-10)

(3) Quantum dots beads array (bar codes) system

 Quantum dots (QDs) show unique characteristics as fluorescence tags. In this laboratory, we have riginally developed ‘beads array’ consisting of beads with different proportions of two kinds of QD. We have prepared 24 kinds of ‘bar code beads’ allowing analysis of 24 kinds of molecules in a single experiment.

III. Cytometry

We have long experience in cytometry that is a routine technology in biomedical research and laboratory medicine. Two types of cytometry, flow cytometry (FCM) and Image cytometry such as laser scanning cytometry (LSC), are routinely available in our laboratory. Both are useful for an analysis of DNA ploidy in tumors. FCM is employed for not only cytomics but also the flow array system, and LSC is a useful technology in the cell array system. Recently, we have started a project concerning an application of quantum dots to cytomics, as mentioned above.

Appendix

Virtual slide system

A virtual slide (VS) system is an interesting digital imaging tool in pathological education of medical doctors and students. The VSs that simulate real light microscopy are used in the pathological department for not only education but also telepathology. Every one can view VSs at the below web site:

introduction