C4B and cancer: In agreement with the literature, peptides from many established plasma proteins including acute phase or common distress proteins such as APOE, C4A, C4B, C4B2, C3, CFI, APOA1, APOC2, APOC4-APOC2, IGHE, ITIH3, and ITIH4 [60, 61] were observed to vary between cancer and control samples.