Chapter 2 - University of British Columbia
Chapter 2 - University of British Columbia
Chapter 2 - University of British Columbia
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
1.12.1 Development <strong>of</strong> tools for genomic analysis<br />
As mentioned earlier, the precursor version <strong>of</strong> SIGMA2 was SIGMA [95]. This tool was built as<br />
an interactive database <strong>of</strong> cancer cell line array CGH pr<strong>of</strong>iles and provided a means for<br />
effective visualization <strong>of</strong> high density array CGH data as well as sharing <strong>of</strong> data. One <strong>of</strong> the<br />
other problems that arose for high density array CGH data is the availability <strong>of</strong> efficient analysis<br />
algorithms to delineate gains and losses. Most algorithms that were developed for array CGH<br />
analysis were developed for arrays with 2000 to 3000 data points and their execution times did<br />
not scale up efficiently when the arrays were generating 100,000 to 1,000,000 data points. To<br />
address this problem, I contributed to the development <strong>of</strong> a segmentation and calling algorithm<br />
named FACADE [100].<br />
1.12.2 Baseline gene expression in non-malignant lung tissue<br />
Though gene expression studies studying malignant samples are important, it is also critical to<br />
define what genes are expressed in non-malignant samples as these are used in reference to<br />
determine aberrant gene expression. There were two studies I was involved with which<br />
addressed this question. First, we examined gene expression <strong>of</strong> non-malignant, smoke<br />
damaged bronchial epithelium using serial analysis <strong>of</strong> gene expression (SAGE) [37]. We found<br />
that there were specific genes that showed high tissue specificity to the bronchial epithelium<br />
with limited representation in other tissues and that there were differences between bronchial<br />
epithelial samples and lung parenchyma, which are samples adjacent to tumors typically used<br />
as non-malignant controls comprised <strong>of</strong> a mixture <strong>of</strong> different cells.<br />
In the study described above, bronchial epithelium samples from current and former smokers<br />
were grouped together. Hence, the next logical question was to assess the effect <strong>of</strong> active<br />
smoking on the bronchial epithelium. In the second study, a group <strong>of</strong> never smoker samples<br />
were added to the groups <strong>of</strong> current and former smokers and the gene expression pr<strong>of</strong>iles <strong>of</strong><br />
the three groups were compared. We first identified a set <strong>of</strong> genes which were differentially<br />
14