Table 4.

Selection of the 36 series of increased and decreased protein markers.

No.	First Protein Name 1	Protein & Protein Groups (Gene Symbol)	Quantified Values (42 Samples)	Fold Change Ratio 2 NEC/Control	ROC Curve AUC	Mann–Whitney Test 3
						p-Value	q-Value
More abundant in NEC stools
1	Carboxypeptidase A1	CPA1	42	3.04	0.82	<0.001	0.003
2	Peroxiredoxin-1	PRDX1;PRDX4	39	2.33	0.82	<0.001	0.003
3	Glutathione reductase, mitochondrial	GSR	42	2.61	0.81	<0.001	0.003
4	Triosephosphate isomerase	TPI1	40	3.90	0.80	0.001	0.004
5	Peroxiredoxin-4	PRDX4	41	2.09	0.80	0.001	0.004
6	Protein S100-A12	S100A12	39	4.12	0.79	0.001	0.004
8	Defensin-5	DEFA5	42	5.09	0.76	0.003	0.009
15	Leukocyte elastase inhibitor	SERPINB1	42	1.62	0.72	0.014	0.023
17	Trehalase	TREH	41	1.63	0.72	0.016	0.023
22	Alpha-2-macroglobulin (1)	A2M	42	3.33	0.83	<0.001	0.002
23	Cathepsin S	CTSS	42	1.91	0.83	<0.001	0.003
24	Alpha-2-macroglobulin (2)	A2M;PZP	42	3.33	0.80	0.001	0.004
25	Probable non-functional Ig kappa variable 2D-24	IGKV2D-24	42	2.09	0.78	0.002	0.007
26	Angiotensin-converting enzyme 2	ACE2	42	2.01	0.77	0.002	0.007
28	Alpha-1-acid glycoprotein 1 (1)	ORM1	42	4.82	0.76	0.003	0.009
32	Ig heavy constant gamma 1	IGHG1	42	1.96	0.73	0.010	0.018
35	Ig lambda variable 8-61	IGLV8-61	42	1.80	0.72	0.016	0.023
40	Sucrase-isomaltase, intestinal	SI	42	1.68	0.70	0.052	0.055
Less abundant in NEC stools
41	Pancreatic secretory granule mb. major gp GP2	GP2	42	0.36	0.88	<0.001	<0.001
42	Sulfate transporter	SLC26A2	41	0.37	0.88	<0.001	<0.001
43	Tetraspanin-1	TSPAN1	42	0.33	0.85	<0.001	0.001
44	Chloride anion exchanger	SLC26A3	40	0.45	0.81	<0.001	0.003
45	Chymotrypsin-like elastase family member 3A (1)	CELA3A	42	0.43	0.80	0.001	0.004
46	Claudin-3	CLDN3,4,6,9	42	0.48	0.77	0.002	0.007
47	Chymotrypsin-C	CTRC	42	0.41	0.77	0.002	0.007
49	Intestinal-type alkaline phosphatase	ALPI	42	0.66	0.75	0.005	0.012
57	Ig lambda variable 3-10	IGLV3-10	42	0.44	0.81	<0.001	0.003
58	Mucin-6	MUC6	42	0.53	0.80	0.001	0.004
59	Mucin-1	MUC1	42	0.43	0.80	0.001	0.004
60	Ig kappa variable 1D-33	IGKV1-33	42	0.64	0.79	0.001	0.004
61	Phospholipase B1, membrane-associated	PLB1	38	0.49	0.79	0.001	0.004
62	Ig heavy variable 2-26	IGHV2-26	38	0.50	0.77	0.002	0.007
64	Tenascin	TNC	41	0.22	0.76	0.003	0.009
65	Colipase	CLPS	42	0.50	0.75	0.006	0.014
76	Ig lambda variable 1-51	IGLV1-51	42	0.57	0.70	0.028	0.032
80	Cadherin-related family member 2	CDHR2	42	0.68	0.70	0.038	0.041

Abbreviation: AUC: area under the curve; gp: glycoprotein; Ig: immunoglobulin; MMP: metalloproteinase; NEC: necrotizing enterocolitis; No.: number; ROC: receiver operating characteristic. ¹ Duplicated first protein names come from protein groups formed by DIA-NN when indifferentiable non-proteotypic precursors can be attributed to more than one gene. ² The fold change ratio was calculated from the mean expression value of both groups. ³ p-values and q-values have been calculated on the standardized expression values using the Mann–Whitney test for the p-value and Benjamini–Krieger–Yekutieli’s two-stage step-up method for the q-value.