Abstract: “Attempts are still in full swing for the detection of differentially expressed genes and using the genes for the detection of early cancer. Each method is with its own simplicity or complexity with the results, yet to portray some degree of confidence level in the designation of a gene as being differentially expressed or not expressed. However, no one statistic is universally optimal and there is seldom any basis or guidance that can direct toward a particular statistic of choice for such complicated gene data. Identifying a subset of genes that are expressed differentially in leukemia types from a large pool of candidates’ genes generated by Golub et al(1999) in microarray experiment has been empirically demonstrated in the study. Principal component analysis on a Box-Cox transformed data exposed clusters of specific leukemia types. Taking into consideration the consistency of a gene expression the relative variance of each gene across the sample expression profiles is determined. A”

Keywords: principal component analysis, relative variance, quadratic discriminant analysis.