I have this general issue of high dimensionality and low number of examples gene expression data. Actually, I have some drug responses for some cancer cells and gene expression for those cells before the application of drugs. I want to relate the response to the gene expression, I mean explain the drug response from the gene expression. I only have around 18 examples and high dimensional gene expression of dimension 25000.
I tried with correlation analysis, see which genes are highly correlated with the drug response for each drug, select the highly correlated genes and used hypergeometric test to see if there are some pathways which is overrepresented in the genes/features for each drug.
However, I haven't got anything significant when running the pathway analysis. Any suggestions, how I should proceed.