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

Table 2 Evaluation of serum pteridine and tryptophan metabolites of lymphatic invasion negative (Group 2/c) and positive (Group 2/d) colorectal cancer patients

Group	Group 2/c(n = 21)	Group 2/d(n = 23)	P value
Tryptophan (μmol/L)1	19.14 ± 1.68	20.62 ± 2.06	0.586
Kynurenine (μmol/L)2	1.45 ± 0.24	0.96 ± 0.11	0.080
Kynurenine/tryptophan	95.85 ± 17.40	83.08 ± 23.13	0.662
Serum neopterin (nmol/L)2	18.43 ± 5.18	15.56 ± 2.78	0.613
Urinary neopterin (μmol neopterin/mol creatinine)1	85.79 ± 11.76	75.68 ± 11.34	0.541
Urinary biopterin (μmol biopterin/mol creatinine)1	76.56 ± 16.44	105.43 ± 17.20	0.234
Urinary neopterin (μmol neopterin/mol creatinine) + urinary biopterin (μmol biopterin/mol creatinine)1	167.42 ± 21.83	177.50 ± 26.82	0.774
IDO (%)	24.04 ± 6.90	44.56 ± 6.11	0.031a

^aP < 0.05, group 2/c vs group 2/d, considered statistically significant;

¹Independent sample t-test;

²Mann-Whitney U test. The comparison displayed that serum indoleamine-2,3-dioxygenase (IDO) activities were strongly predictive for lymphatic invasion.