Identifying differentially expressed genes based on their expressions in leukemia

Introduction: In 1999, Golub invented a new reasonable and more efficient approach to recognize acute Leukemia cases based on gene expression data. Studying on 6817 genes derived from 38 patients, they finally introduce a complex inventory statistical method to diagnose Leukemia patients in earlier stage. Their result was absolutely outstanding, without any mistake in patient diagnosis the result perfectly (100%) assigned tumors to known classes correctly. Here, in this study, we want to introduce a simpler method to distinguish Differentially Expressed (DE) genes and use Golub approach as a test case to evaluate our results. Materials and Methods: We used the same data as Golub study that were produced by oligonucleotide microarry. Several statistical methods such as t-test, Wilcoxon test and permutation test were applied to identify DEs. Results: The Westfall and Yang based on t-statistic at significant level 0.015 (α= 0.015) recognized 48 genes significant (or DE). Of those 28 genes (58%) were exactly similar to Golub study and the rest, 20 genes (42%), were different. However, with these 48 genes, the result of assigning tumors to known classes is completely as identical as that of of Golub study. Conclusion: The result of assigning tumors to known classes with these 48 genes is completely as identical as that of Golub study.