I´m using bioconductor and I want to extract the tissue name of the cel files (not the file name itself because a lot of cel files with different names can be related to the same tissue) in order to create a principal component analysis scatter plot where each group name is equals to tissues names. I dont want to define every group manually but I dont know if there exists an attribute wich provides that information inside cel files.

I´m using oligo package. In the example image every cluster is a tissue and every dot is a cel file