Which Test: selecting two predictors of disease outcome

#1
Hi

I'm wondering which test I should use to analyzed my data.
What I have are two groups: progressing and non-progressing patients; and I want to see if this can be predicted by the expression values of any two genes, I want to analyze every possible pair of the genes I have tested, to see which pair is the most significant.
Any thoughts on which test I should use, also how to run it?

Thanks for your help everyone
 
#2
First: select genes that are of potential interest. If you have a very large number of genes, use a threshold for the CV (coefficient of variance = variance filtering) or a minimal mean fold change between the groups to pre select genes. Next, test the individual genes for difference between the groups (t-test or mann whitney u test depending on the sample size).

Next: combine genes with relevant and significant differences between the groups in a logistic regression model in pairs. Dependent: phenotyp (0 non progression, 1 progression). Regression coefficients will be the OR for progression, i.e. a quantification of the predictive strength of one gene for the progressive phenotype corrected for the influence of the second gene. <1 = predictive for non progression >1=contributes to progressive phenotype.

Best, Martin