How to normalize NCI-60 gene expression data

Question

[hAjmal]

Hi, I want to know how would I do log2 median centered normalization on gene expression of NCI-60 cancer cell lines? The "exp" is the Z-scores, I need log2 median centered data.

[Pietro]

If data are already standardized, then you should check how the z-scores were calculated.

Usually z-scoring means subtracting population mean and then dividing by standard deviation, but for gene expression can also mean subtracting row mean and dividing by row SD. See here.

If you can't find these info you can explore the data in R and check mean median and SD.