Table 6.

Nonparametric correlation between the ratios of the studied parameters, the Breslow thickness, Clark level, and the melanoma stage.

		Kyn/Trp	KYNA/Trp	KYNA/Kyn	5-HIAA/Trp	DHICA/Trp	5-HIAA/DHICA	IS/Trp
KYNA/Trp	rho	0.807 **
	p-value	1.07 × 10−31
KYNA/Kyn	rho	−0.665 **	−0.176 *
	p-value	2.66 × 10−18	0.043
5-HIAA/Trp	rho	0.209 *	0.166	−0.194 *
	p-value	0.019	0.065	0.030
DHICA/Trp	rho	0.289 **	0.264 **	−0.086	−0.093
	p-value	0.001	0.003	0.345	0.308
5-HIAA/DHICA	rho	0.187 *	0.139	−0.175	0.193 *	0.131
	p-value	0.040	0.128	0.055	0.034	0.153
IS/Trp	rho	0.179 *	0.160	−0.101	0.521 **	0.223 *	0.065
	p-value	0.039	0.067	0.249	4.86 × 10−10	0.013	0.481
Breslow thickness	rho	0.011	0.014	−0.064	0.039	−0.326 *	0.296 *	−0.019
	p-value	0.926	0.911	0.601	0.766	0.011	0.024	0.875
Clark level	rho	0.034	0.056	−0.136	−0.209	−0.244	0.104	−0.126
	p-value	0.777	0.643	0.257	0.101	0.058	0.434	0.294
Melanoma stage	rho	0.032	−0.009	−0.159	−0.012	−0.516 **	0.394 **	−0.092
	p-value	0.775	0.935	0.154	0.921	3.48 × 10−6	0.001	0.409

Trp—tryptophan in µmol/mmol of creatinine; Kyn—kynurenine in µmol/mmol of creatinine; KYNA—kynurenic acid in µmol/mmol of creatinine; DHICA—5,6-dihydroxyindole-2-carboxylic acid in µmol/mmol of creatinine; IS—indoxyl sulfate in µmol/mmol of creatinine; 5-HIAA—5-hydroxyindole-3-acetic acid in µmol/mmol of creatinine; rho—Spearman’s rho correlation coefficient; significance 2-tailed; *—correlation is significant at the 0.005 level; **—correlation is significant at the 0.010 level.