Application of High-Throughput Tissue Microarray Technology in Cancer Research

This dissertation, "Application of High-throughput Tissue Microarray Technology in Cancer Research" by Dan, Xie, 謝丹, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of Thesis entitled Application of High-throughput Tissue Microarray Technology in Cancer Research Submitted by Xie Dan For the degree of Doctor of Philosophy at the University of Hong Kong In May 2004 Tissue microarray (TMA) is a new high-throughput technology which allows rapid and simultaneous visualization of molecular targets in thousands of tissue specimens at a time under highly standardized condition, either at the DNA, RNA or protein level. My objectives in this study were to (1) construct multiple tumor tissue TMAs containing a series of different tumor types and normal tissues from Chinese patients; (2) use multi-tumor TMAs to screen the expression of a novel candidate oncogene, eIF-5A2 by immunohistochemistry (IHC) and evaluate it's oncogenic function in tumorigenesis; and (3) test the abnormalities of some cancer-related genes, such as β-catenin, p16, E-cadherin, c-myc, AIB1, clusterin, EGFR and Tp53 in several tumor-specific TMAs, so as to investigate their clinico-pathological significances. In this study, I firstly constructed multiple tumor tissue TMAs containing a total of 4671 human tissue samples, including 1619 cases of primary tumors from 11 different tumor types, 234 cases of matastases or recurrent tumors from i 4 tumor types and 505 samples from 8 normal tissues. I then used IHC to screen the protein expression of EIF-5A2 in this multi-tumor tissue TMAs and found that the high-level expression of EIF-5A2 was more frequently occur in human cancer as compared to paired normal tissue or benign tumor lesion. In addition, high-level expression of EIF-5A2 was evaluated to be significantly associated with patient's later clinical stage in several tumor types including ovarian cancer, colorectal cancer, lung cancer and bladder cancer. These studies demonstrated that multi-tumor TMA would be extremely valuable to understanding the similarities and differences in biology of the many different categories of human cancer. In tumor-specific TMA, by using a progression colorectal cancer (CRC)- TMAs, I found that the expression of β-catenin and p16 was quantitatively increased from normal mucosa to premalignant adenoma, to primary carcinoma and to lymph node metastatic carcinoma, and the frequency of overexpression of β-catenin and p16 in lymph node metastases was significantly higher than that in distant metastases, suggesting that the overexpression of β-catenin and/or p16 might be involved in CRC lymph node metastasis but not in distant metastasis. Meanwhile, a significant correlation between overexpression of AIB1 and p53 and aneuploid DNA content in CRCs was evaluated by the same TMA of CRC. Similarly, by using a progression ovarian cancer-TMA, I observed that the ii frequency of up-regulated expression of clusterin increased from the normal ovary to adenoma, borderline tumor and invasive cancer. In addition, by using another tumor-specific TMA containing 2 subtypes of glioblastom, we revealed that amplification/overexpression of EGFR in Chinese glioblastoma may be associated closely with the patients age but not with the tumor's clinical subtype. All these results demonstrated that the TMA technology could provide an ideal approach in cancer research and it will facilitate rapid translation of basic research to clinical applications in the future.