S100A9 and neoplasm: While we could not conduct a complete survey of all possible Zn binding proteins, we tested for the expression of six Zn-binding proteins in our OPSCC cohort that we initially detected in OPSCC by mass spectroscopy—Lipocalin-1, AZGP1, albumin, S100A7, S100A8 and S100A9—and we found that only AZGP1 expression was significantly higher in HPV-positive OPSCC tumor cells.