Targeted metabolomics in colorectal cancer: a strategic approach using standardized laboratory tests of the blood and urine

Figures & data

Figure 1 Schematic representation of pyruvate metabolism, illustrating selected byproducts.

Table 1 Differences in laboratory investigations between patients with metastatic and local CRC

Investigations	Reference intervals	Metastatic CRC			Local CRC			p-value^*
		Proportion above normal (%)	Mean (SD)	Median (IQR)	Proportion above normal (%)	Mean (SD)	Median (IQR)
24-hour urine citrate (mmol/day)	1.6 to 6.0	13% (2/15)	4.24 (4.57)	3.25 (1.50 to 4.90)	0% (0/7)	2.90 (1.51)	3.00 (1.90 to 4.30)	NS^#
Lactate (mmol/L)	0.5 to 2.2	10% (2/20)	1.4 (0.6)	1.4 (0.8 to 2.0)	11% (1/9)	1.2 (0.5)	1.0 (0.9 to 1.3)	NS
Venous pH	7.32 to 7.42	16% (3/19), high	7.38 (0.14)	7.35 (7.32 to 7.40)	0% (0/9), high	7.36 (0.04)	7.37 (7.34 to 7.37)	NS^#
		21% (4/19), low			11% (1/9), low
Venous pCO2 (mmHg)	38 to 50	47% (9/19)	50.2 (9.4)	48.0 (41.0 to 57.0)	27% (3/11)	42.8 (9.0)	45.0 (37.0 to 52.0)	0.045
Calculated HCO3 (mmol/L)	24 to 30	16% (3/19)	27.6 (2.5)	27.0 (26.0 to 30.0)	0% (0/9)	26.0 (3.4)	27.0 (24.0 to 29.0)	NS
Measured serum osmolality (mmol/kg)	280 to 300	21% (4/19)	295.7 (4.6)	295.0(292.0 to 298.0)	0% (0/5)	292.0 (3.2)	291.0 (290.0 to 293.0)	NS
Calculated serum osmolality (mmol/kg)	^—	^—	292.0 (5.1)	293.0(290.0 to 296.0)	^—	283.3 (9.6)	290.0 (282.0 to 292.0)	0.018^#
Osmolar gap	<10	5% (1/19)	2.1 (4.0)	1.9 (-0.4 to 3.9)	25% (1/5)	5.5 (6.8)	3.5 (0.7 to 6.1)	NS
Plasma sodium (mmol/L)	135 to 145	0% (0/20)	140.1 (1.8)	140.0(139.0 to 141.5)	0% (0/16)	137.5 (3.8)	138.5 (136.0 to 140.0)	0.014^#
Plasma urea (mmol/L)	3.5 to 7.2	45% (9/20)	6.6 (2.0)	6.7 (4.7 to 7.9)	13% (2/15)	5.0 (2.1)	5.7 (2.9 to 6.5)	0.032
Random plasma glucose (mmol/L)	3.8 to 11.0	0% (0/20)	6.2 (1.5)	5.8 (5.1 to 7.0)	0% (0/14)	5.6 (0.7)	5.8 (5.1 to 6.1)	NS^#
AG	5 to 17	20% (3/15)	9.5 (3.3)	8.0 (7.0 to 12.0)	7% (1/14)	8.3 (2.4)	8.0 (7.0 to 10.0)	NS^#
ALT (U/L)	10 to 40	0% (0/12)	22.1 (9.6)	20.5 (14.5 to 30.5)	0% (0/8)	16.0 (5.7)	15.5 (10.5 to 21.0)	NS
Ketones	^—	^—	Negative in all patients	^—	^—	Negative in all patients	^—	^—

Notes: *Two-sample t-tests were employed for normally distributed variables and the equivalent nonparametric (two-sample Wilcoxon) test was employed for the remaining variables. In all cases where statistically significant results were identified, the corresponding chi-square test of proportions was also statistically significant. ^#Not normally distributed.

Abbreviations: ALT, alanine aminotransferase; AG, anion gap; CRC, colorectal cancer; IQR, interquartile range; SD, standard deviation; NS, non-significant.

Table 2 Values of plasma total CO₂ in cancer patients and in the hospital inpatient and outpatient populations, from January to December 2014

	Outpatients attending cancer center (n= 1,825)	Outpatient hospital, general population (n= 1,783)	Inpatient hospital population (n=5,931)
Median (IQR) total CO2 (mmol/L)	27 (25 to 28)	24 (23 to 26)*	23 (20 to 27)*
Percentage of patients with abnormally high pCO2	229 (13)	20 (1)*	684 (12)
(>29 mmol/L), n (%)
Percentage of patients with abnormally low pCO2	60 (3)	278 (16)*	2,208 (37)*
(<22 mmol/L), n (%)

Note: *p-value < 0.05 when compared with cancer center population.

Abbreviation: IQR, interquartile range.