I am trying to analyze the proteomics data published on synapse.org. In the MayoRnaSeq data neurodegenerative diseases like AD, PSP, pathological aging, etc, there is one cohort with 5 batches and 3 conditions (AD, PSP, and control) in all the 5 batches, there are terms egis and mgis. I am writing because I am unable to understand what those terms mean and why in my PCA, (unable to upload the plot here) these form different clusters as outliers would do. Is it advisable to remove these values from the dataset or do they have important information? Please see the below as an illustration to explain my question. Such terms are present in all batches (b1,b2,b3,b4,b5) mayo_b5_egis_02 mayo_b5_egis_24 mayo_b5_egis_45 mayo_b5_mgis_01 mayo_b5_mgis_23 mayo_b5_mgis_44 Also, these data are not annotated to any conditions (AD, PSP or control ) The data has the following synapseID: syn7431988 and the file I am trying to analyze is Mayo_Proteomics_TC_proteinoutput.txt I tried to look at the Mayo_Proteomics_TC_searchparameters.xml But couldn't understand the 'egis' and 'mgis' terms that appeared in all the 5 batches of the data. I will be grateful if I could understand the above-mentioned parameters and can get answers to my questions.