Tryptophan catabolism increases in breast cancer patients compared to healthy controls without affecting the cancer outcome or response to chemotherapy

Table 4 Kyn, Trp and Kyn/Trp ratio in breast cancer subtypes

	Group (N of pts)	Kyn		Trp		Kyn/Trp ratio
	Group (N of pts)	Median ± SD	p value	Median ± SD	p value	Median ± SD	p value
Luminal A (60 pts)	PCR (0)	NA	NA	NA	NA	NA	NA
	No pCR (13)	1.710 ± 0.684	NA	36.70 ± 8.26	NA	0.042 ± 0.019	NA
	No relapse (53)	1.775 ± 0.582	0.982	48.17 ± 13.02	0.442	0.038 ± 0.014	0.542
	Relapse (7)	1.717 ± 0.501	0.982	44.67 ± 5.88	0.442	0.043 ± 0.009	0.542
Luminal B (89 pts)	PCR (23)	1.887 ± 0.327	0.001**	44.77 ± 14.17	0.455	0.045 ± 0.011	0.029*
	No pCR (42)	1.580 ± 0.463	0.001**	43.47 ± 8.51	0.455	0.036 ± 0.011	0.029*
	No relapse (79)	1.807 ± 0.463	0.194	43.87 ± 10.53	0.447	0.038 ± 0.011	0.119
	Relapse (10)	1.653 ± 0.389	0.194	46.93 ± 8.42	0.447	0.035 ± 0.006	0.119
HER2-enriched (14 pts)	PCR (7)	1.757 ± 0.790	0.234	39.73 ± 8.12	0.836	0.045 ± 0.018	0.295
	No pCR (6)	2.43 ± 0.956	0.234	42.42 ± 5.03	0.836	0.063 ± 0.028	0.295
	No relapse (10)	1.828 ± 0.786	0.454	37.80 ± 6.67	0.076	0.047 ± 0.023	1
	Relapse (4)	2.398 ± 1.135	0.454	46.13 ± 2.94	0.076	0.049 ± 0.026	1
TNBC (39 pts)	PCR (13)	1.707 ± 0.476	0.853	44.43 ± 7.98	0.511	0.037 ± 0.008	0.353
	No pCR (22)	1.777 ± 0.449	0.853	41.97 ± 10.87	0.511	0.042 ± 0.013	0.353
	No relapse (39)	1.648 ± 0.450	0.707	44.78 ± 10.73	0.440	0.037 ± 0.012	0.761
	Relapse (7)	1.813 ± 0.437	0.707	42.00 ± 4.65	0.440	0.042 ± 0.011	0.761

The corresponding p values for patients showing or not a pCR and for patients with or without relapse are reported in the table. A significance level of 0.05 is accepted (in italics)
Median value of Kyn, Trp and Kyn/Trp ratio in the different breast cancer subtypes according to the response to chemotherapy and relapse tested by the mean of the Mann–Whitney U test
Kyn kynurenine, Trp tryptophan, SD standard deviation, PCR pathological complete response, TNBC triple-negative breast cancer

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