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Sample A: Cover Page of Thesis, Project, or Dissertation Proposal

Sample A: Cover Page of Thesis, Project, or Dissertation Proposal

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from each patient: 2 n<strong>or</strong>mal looking that are adjacent to the tum<strong>or</strong> and 2 adenocarcinoma<br />

samples); one <strong>of</strong> the n<strong>or</strong>mal samples is missing, presumably f<strong>or</strong> high tum<strong>or</strong> content [4]. These<br />

sample biopsies were harvested using microdissection techniques and then snap-frozen [4]. The<br />

final BaFL interpretation <strong>of</strong> the sample included 17 tum<strong>or</strong> samples and 14 n<strong>or</strong>mal (i.e. adjacent)<br />

samples. These two datasets had a common group <strong>of</strong> 325 ProbeSets that were identified as<br />

significantly differentially expressed between the diseased and n<strong>or</strong>mal states, based upon Welch’s<br />

t-test <strong>of</strong> BaFL-provided values, applied at the ProbeSet (aggregate) level, described in detail in<br />

Chapter 3 [9]. The latent structure <strong>of</strong> these 325 ProbeSets is presented as a final piece <strong>of</strong><br />

evidence showing why these ProbeSets should serve as the foundation f<strong>or</strong> the feature selection,<br />

and particularly why the BaFL interpretation <strong>of</strong> these ProbeSets’ signal intensities is preferred.<br />

Feature Selection<br />

Using the BaFL-provided values f<strong>or</strong> these genes, the Bonferroni c<strong>or</strong>rection was applied to each<br />

dataset; c<strong>or</strong>rection cut<strong>of</strong>fs were less than 1.18e-05 f<strong>or</strong> the Bhattacharjee data and 7.68e-06 f<strong>or</strong> the<br />

Stearman data.<br />

Q " p / t , (4.1)<br />

where { Q , 1} if p is less than the c<strong>or</strong>rection. The number <strong>of</strong> total tests is represented by t, and p<br />

represents the p-value <strong>of</strong> Welch’s t-test [8, 9]. This resulted in 79 Bonferroni c<strong>or</strong>rected ProbeSets<br />

out <strong>of</strong> the 480 Bhattacharjee DE ProbeSets and 352 Bonferroni c<strong>or</strong>rected ProbeSets from the<br />

3,162 Stearman DE ProbeSets; the intersection set was 30 ProbeSets. The Bonferroni c<strong>or</strong>rection<br />

was applied also to both <strong>or</strong>iginal BaFL-interpreted 4,253 Bhattacharjee ProbeSets and 6,506<br />

BaFL interpreted Stearman ProbeSets. The resulting intersection <strong>of</strong> ‘most significant’ ProbeSets<br />

94

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