Table 4. Cox's proportional hazard model estimating the prognostic impact of PROX1 expression and of established prognostic factors for LGG on survival (n=116).

		Full model			Stepwise model
Prognostic factor		Risk ratio	Confidence limits	P-value	Risk ratio	Confidence limits	P-value
Clinical variables
Age at onset	<40 vs ⩾40 years	1.24	0.87–187	0.3167	—	—	—
Performance status	KPS >80 vs ⩽80	0.95	0.58–1.60	0.8380	—	—	—
Tumour size	⩾6 vs <6 cm	1.37	0.83–2.21	0.2184	—	—	—
Tumour crossing midline	Yes vs no	1.71	1.09–2.67	0.0211	1.71	1.11–2.61	0.0161
Contrast enhancement	Yes vs no	1.62	1.06–2.47	0.0248	1.52	1.01–2.28	0.0446
Histology	A vs OA/O	1.22	0.99–1.51	0.0624	1.22	1.00–1.50	0.0557
Extent of resection	GTR vs not	0.75	0.43–1.27	0.2951	—	—	—
Molecular variables
Ki-67 expression	<4% vs ≅4%	0.93	0.51–1.65	0.8143	—	—	—
IDH1 mutation	Yes vs no	0.57	0.35–0.95	0.0313	0.61	0.39–1.02	0.0575
PROX1-positive cells	⩾10% vs <10%	1.61	1.04–2.47	0.0310	1.63	1.07–2.45	0.0237

Abbreviations: KPS=Karnofsky performance status; A=astrocytoma; OA=oligoastrocytoma; O=oligodendroglioma; GTR=gross total resection; IDH=isocitrate dehydrogenase; LGG=low-grade gliomas.

Factors removed from the model using the backwards exclusion method (p-to-remove >0.10): Performance status (at step 1, P=0.8380), Ki-67 expression (at step 2, P=0.8627), age at onset (at step 3, P=0.3101), extent of resection (at step 4, P=0.2742), tumour size (at step 5, P=0.1057).