Myeloid derived suppressor cells (MDSC) accumulate in patients and animals with cancer where they mediate systemic immune suppression and obstruct immune based cancer therapies. To determine how inflammation enhances MDSC levels and activity we used mass spectrometry to identify proteins produced by MDSC induced in highly inflammatory settings. This experiment includes six "shotgun" RAW files for peptides produced through trypsin digestion. Accurate precursor masses were measured in the FT and unit resolution fragment ions were measured in the linear ion trap. Experimental hierarchy: inflammatory4T1IL1b/tech1 balbc_4T1_IL1b_1.mzML inflammatory4T1IL1b/tech2 balbc_4T1_IL1b_2.mzML conventional4T1/tech1 Olesya-4T1_balbc_1.mzML conventional-4T1/tech2 Olesya-4T1_balbc_2.mzML TLR4knockout-4T1/tech1 TLR4_4T1_1.mzML TLR4knockout-4T1/tech2 TLR4_4T1_2.mzML