Specific Investigation of Sample Handling Effects on Protease Activities and Absolute Serum Concentrations of Various Putative Peptidome Cancer Biomarkers

Table 3 Measured concentrations of the various peptides in serum from breast cancer (BC) patients and controls (CO) after direct measurement or after 24 h incubation at RT

		Direct measurement			After 24 h at RT
		Median concentration [Range]^a (ng/ml)		P value^c	Median concentration [Range]^a (ng/ml)		P value^c
Peptide	n	BC	CO	P value^c	BC	CO	P value^c
Fib-α _[605–629]	9	157.9 [81–238]	186.6 [85–493]	.402	336.4 [112–423]	319.4 [180–571]	.453
C4a _{[1337–1350]}	9	1.7 [0.5–5]	2.2 [0.5–8]	.251	1.7 [1–2]	1.3 [0.5–3]	.566
Bradykinin ^d	9	94.2 [38–165]	76.3 [57–140]	.566	35.1 [8–102]	38.4 [26–98]	.566
Des-Arg⁹-bradykinin	9	97.6 [69–152]	87.3 [46–168]	.402	66.3 [13–120]	78.9 [59–114]	.453
ITIH₄-21	13	6.2[1–54]	3.1 [1–11]	.118	40.1 [4–139]	33.0 [1–84]	.555
ITIH₄-22	22	1.1 ^b [1–18]	0.5 ^b [1–5]	.135	6.3 [1–53]	4.0 [1–13]	.046
ITIH₄-25	13	2.7 [1–22]	1.4 [1–2]	.061	28.3 [6–358]	20.8 [4–74]	.033
ITIH₄-26	13	6.3 [2–672]	4.0 [1–8]	.077	14.3 [2–605]	8.7 [3–44]	.144
ITIH₄-27	13	1.7 [1–22]	1.0 [1–4]	.274	5.0 [1–43]	2.8 [1–16]	.077
ITIH₄-28	13	4.2 [2–50]	2.4 [1–7]	.061	31.2[4–82]	23.6 [1–44]	.522
ITIH₄-29	13	5.2 [1–101]	2.7[1–6]	.043	25.9 [4–306]	13.7 [1–58]	.043
ITIH₄-30	13	37.2 [5–4078]	19.0 [3–58]	.038	33.6 [5–279]	20.7[6–94]	.038

^aMeasurements below the LLOQ are set at 1/2 LLOQ; measurements above the ULQ are presented as the extrapolated value
^bQuantified with two methods (13 samples together with the ITIH₄-derived peptides and nine with the putative breast cancer markers). All values below 1 ng/ml were set at 0.5 ng/ml
^cUsing Mann–Whitney U test. Values in bold indicate P values <.05
^dResults for bradykinin were similar as for bradykinin, though at lower concentrations and are not presented

ISSN: 1559-0275