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

Table 1 Serum tryptophan, kynurenine and neopterin, urinary neopterin and biopterin of cancer-free group (Group 1) and colorectal cancer patients (Group 2)

Group	Group 1(n = 43)	Group 2(n = 44)	P value
Age (yr)1	62.06 ± 2.07	60.95 ± 2.11	0.708
Tryptophan (μmol/L)1	21.95 ± 1.03	19.91 ± 1.33	0.254
Kynurenine (μmol/L)2	1.03 ± 0.19	1.20 ± 0.13	0.042a
Kynurenine/tryptophan1	41.31 ± 3.62	89.47 ± 14.32	0.006a
Serum neopterin (nmol/L)2	13.28 ± 1.08	16.93 ± 2.84	0.634
Urinary neopterin (μmol neopterin/mol creatinine	63.54 ± 5.64	80.45 ± 8.09	0.090
Urinary biopterin (μmol biopterin/mol creatinine)1	67.33 ± 6.22	91.41 ± 12.00	0.038a
Urinary neopterin (μmol neopterin/mol creatinine) + urinary biopterin (μmol biopterin/mol creatinine)1	129.83 ± 9.42	172.60 ± 17.17	0.048a

^aP < 0.05, Group 2 vs Group 1 considered statistically significant;

¹Independent sample t-test;

²Mann-Whitney U test. Colorectal cancer patients showed more than two times increase in overall serum kynurenine-tryptophan ratio and a non-significant rise in the activity of pteridine pathway when compared with the cancer-free patients (Group 1).