Relationship between indoleamine 2,3-dioxygenase activity and lymphatic invasion propensity of colorectal carcinoma

Table 3 Evaluation of serum pteridine and tryptophan metabolites of lymph node metastasis negative (Group 2/a) and positive (Group 2/b) colorectal cancer patients

Group	Group 2/a(n = 32)	Group 2/b(n = 12)	P value
Tryptophan (μmol/L)1	18.04 ± 1.39	23.98 ± 2.98	0.047a
Kynurenine (μmol/L)1	1.33 ± 0.17	0.87 ± 0.14	0.139
Kynurenine/tryptophan1	103.20 ± 18.13	53.27 ± 17.36	0.121
Serum neopterin (nmol/L)2	17.78 ± 3.68	14.67 ± 3.94	0.368
Urinary neopterin (μmol neopterin/mol creatinine)1	83.07 ± 9.76	71.29 ± 12.96	0.552
Urinary biopterin (μmol biopterin/mol creatinine)1	96.87 ± 13.83	69.56 ± 23.13	0.371
Urinary neopterin (μmol neopterin/mol creatinine) + Urinary biopterin (μmol biopterin/mol creatinine)1	179.95 ± 20.48	143.23 ± 24.95	0.400
IDO (%)1	30.32 ± 5.74	48.75 ± 8.30	0.089

^aP < 0.05; group 2/a vs group 2/b, considered statistically significant;

¹Independent sample t-test;

²Mann-Whitney U test. The comparison displayed that serum indoleamine-2,3-dioxygenase (IDO) activities were not predictive for lymph node dissemination alone.