CD8A and colorectal carcinoma: When performing preliminary correlations of the MALD-MSI data with IHC, the highest signal intensity for m/z 900.6 [PS(44:1)] and m/z 901.5 [PI(O-40:3] were found in regions of CRC tissue with a high number of CD3 and, in particular CD8, T lymphocytes (Figure 5), with a negligible intensity being observed in those regions with scarce TIL content.