Table 2. Baseline plasma YKL-40 and patient characteristics.

	YKL-40, ng/mL		YKL-40, percentilea
	Median	pb	Median	pb
Gender		0.40		0.28
Female	62		64
Male	67		67
Age		< 0.0001		0.07
≤ 65 years	57		64
> 65 years	98		73
Race		0.14		0.24
Non-white	90		78
White	64		64
WHO PS		< 0.0001		0.001
0	53		56
1	78		73
Type of surgery		0.03		0.0496
Biopsy only	65		64
Partial resectionc	69		70
Complete resection	55		60
Smoking status		0.31		0.93
Current smoker	57		60
Never smoker	63		65
Past smoker	70		67
Molecular subtyped (n = 305)		0.49		0.41
Proneural	67		61
Mesenchymal	70		70
Proliferative	61		63

^aPercentile of YKL-40 according to the established normal YKL-40 level in healthy individuals [39].

^bp value from Mann-Whitney U test for two groups or Kruskal-Wallis test for > 2 groups comparing biomarker levels across the groups.

^cPartial resection meant that some extent of tumor debulking was undertaken but macroscopically visible tumor was left behind. This should be contrasted with either diagnostic biopsy only or removal of all visible tumor (complete resection). Since patients with partial resections have larger tumor burdens, higher levels of YKL-40 are to be expected.

^dMolecular subtype as defined in the study by Philips et al. 2006 [24].