This study completed the analysis of mutational frequencies and clinicopathological patterns of six EGFR pathway-related genes (EGFR, HER2, HER4, KRAS, BRAF and MET) in 212 resected lung adenocarcinomas (AD) from 98 male and 114 female Chinese patients without prior chemotherapy or tyrosine kinase inhibitor (TKI) therapy. Genomic DNA and cDNA sequencing, quantitative PCR and fluorescence in-situ hybridization (FISH) were employed to investigate mutation and amplification status of the relevant genes. Overall, more than 75% of tumours were detected to harbour mutations or amplification in one of these six genes. The commonest mutation was found to involve EGFR, comprising 60.38% of cases, followed by KRAS (9.43%), HER2 (2.36%), MET (2.36%), BRAF (1.42%) and HER4 (0.47%). Four somatic mutations in MET exon 14 splicing region were found, leading to alternative splicing and a transcript lacking exon 14. Two of the MET mutant tumours and one MET wild-type tumour showed MET amplification of more than 3.5 fold increase in copy number. Mutations of EGFR were significantly more frequent in female (p = 0.0196), non-smokers (p < 0.001) and well differentiated tumours (p = 0.0209). KRAS mutations showed significant association with male (p = 0.0099) and smoking history (p = 0.0011). A novel HER2 D769Y mutation was found and HER2 mutations were associated with smokers (p = 0.0013) and poorly differentiated tumours (p = 0.0147). BRAF, MET mutations and MET amplification were not associated with clinicopathological factors. Mutations were mutually exclusive except for two cases with KRAS and HER4/BRAF. MET amplification was co-existent with MET mutations in two cases. MET amplification was found to negatively correlate with disease-free and cancer-specific survivals. The results suggested that MET amplification may contribute to disease progression and could be a therapeutic target in primary lung AD in Hong Kong Chinese patients. / published_or_final_version / Pathology / Master / Master of Medical Sciences

abstract / toc / Physiology / Master / Master of Philosophy

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 193-205).

Thesis (Ph. D.)--University of Virginia, 1997. / Spine title: [alpha]₂-M & LRP in atherosclerosis. Includes bibliographical references (180-195). Also available online through Digital Dissertations.

Thesis (Ph.D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 140-172) Also available in print.

Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

Thesis (M.C.E.)--University of Delaware, 2007. / Principal faculty advisor: Dionisios G. Vlachos, Dept. of Chemical Engineering. Includes bibliographical references.

<p> DER, the Drosophila Epidermal Growth Factor Receptor (DEgfr) is the only known fly orthologue of vertebrate Neu/ErbB2 receptor tyrosine kinase family. Receptor Tyrosine Kinases (RTKs) like DER and ErbB2 play an important role in regulating cell differentiation, cell proliferation and cell survival in metazoan animals. Neu/ErbB2 is over-expressed in 20-30% human breast cancers, which correlates with poor clinical prognosis in cancer patients. </p> <p> Our previous studies showed that rat-NeriJErbB2 could successfully signal in vivo using Drosophila adaptor and second messenger molecules. Here we regenerated the transgenic fly lines with various neu add-back alleles. We further re-established mis-expression phenotypes in various adult structures such as wings and eyes, the tissues known to require DEgfr signaling. By using genetic approach, we have demonstrated that the tyrosine residue at the 1028 site (NeuYA), might have an inhibitory role in RTK signaling. In addition we have already generated a number of double add-back neu alleles where tyrosine site at the 1028 site (neuYA) was added back to another Neu allele and made neuYAB, neuYAc neuYAD and neuYAE. Transgenic flies with these alleles will be generated to further study the inhibitory role of Neu^YA. </p> <p> Finally, our on going large-scale genetic screening is likely to reveal the component(s) of NeuYE (Y1253) pathway that does not utilize the function of Ras. </p> / Thesis / Master of Science (MSc)

Improved corneal epithelial cell growth over artificial cornea materials is required to improve device retention within the eye. In this work, varying concentrations of epidermal growth factor (EGF), a potent mitogen for epithelial cells, were immobilized to polydimethylsiloxane (PDMS) substrates, and the cellular response was analyzed. Three methods were developed to bind EGF to PDMS via polyethylene glycol (PEG) tethers. 1) Plasma Modification: EGF was first reacted with homobifunctional NHS2PEG and then bound to allylamine plasma-modified PDMS. 2) Hydrosilylation: PDMS was modified with heterobifunctional allyl-PEG-NBS and then EGF was attached to the surface-bound PEG. 3) Thiol Modification: EGF was first reacted with heterobifunctional NHS-PEG-maleimide and then bound to thiol-modified PDMS. Using Method 1 (Plasma Modification), 40 to 90 ng/cm2 of EGF was bound, however 70% of this was adsorbed even under optimized EGF-PEG reaction conditions. Cells rapidly grew to confluence on these surfaces, and cell counts increased significantly compared to control surfaces. Extracellular matrix protein production was also increased on the EGF-modified surfaces, corresponding to significantly higher levels of cell adhesion observed under a detachment force. Modification by Method 2 (Hydrosilylation) resulted in 10 to 300 ng/cm2 of bound EGF, of which 20% was adsorbed. However, despite increased EGF binding homogeneity, the cell growth was slower on these surfaces than on those prepared by Method 1, and coverage was non-uniform at all EGF concentrations. This is likely due to a higher underlying PEG density, and binding of the PEG and EGF in clusters on the surface. Simultaneous tethering of the cell adhesion peptide YIGSR had no further effect on cell coverage. Using Method 3 (Thiol Modification), 24 to 65 ng/cm2 of EGF was bound, of which 22% was adsorbed. This method enables more homogeneous EGF surface binding than Method 1, with a lower PEG density than Method 2. However, free thiol groups were inhibitory to corneal epithelial cell growth, even in the presence of bound EGF. Defunctionalization of free thiols by reaction with 3-maleimidopropionic acid restored cell growth and morphology on the PDMS, and may hence allow for retention of the proliferative effect of the EGF. These results indicate that while tethering of EGF to PDMS can improve the coverage by corneal epithelial cells, and presents a promising strategy for modification of polymeric artificial cornea materials, the effects are highly dependent on the underlying surface chemistry. / Thesis / Doctor of Philosophy (PhD)