Of note, while the most potent MDSC (SCCL-MT1 and SCC-4-induced) blocked both T cell proliferation and IFNγ production, weaker HNSCC-induced CD33+ suppressor cells preferentially inhibited T cell proliferation (CAL-27 or SW 451-induced) or IFNγ production (FaDu-induced). Here, CD33 is linked to head and neck squamous cell carcinoma.