Table 1. Characteristics of the studies.

Author	Publication year	Samples	SHMT type	SHMT detection	Cut-off value of SHMT expression	Follow-up (month)	Study period	Country	Source of HR
Shi et al.	2019	130	SHMT2	IHC	Staining scores with intensity and proportion (>3)	46.6	2008–2016	China	Reported
Ji et al.	2019	144	SHMT2	IHC	Staining scores with intensity and proportion	36	2006–2017	China	Reported
Liu et al._GC	2019	58	SHMT2	IHC	Staining scores with intensity and proportion (>4)	Until May 2018	2010–2013	China	Reported
Liu et al._EC		65	SHMT2	IHC	Staining scores with intensity and proportion (>4)	Until May 2018	2010–2013
Liu et al._CC		60	SHMT2	IHC	Staining scores with intensity and proportion (>4)	Until May 2018	2010–2013
Ning et al.	2018	100	SHMT2	IHC	Staining scores including intensity and proportion (>4/12)	37	2005–2015	China	Reported
Noguchi et al.	2018	103	SHMT2	IHC	Staining scores with proportion (≥2/2)	60.9	2007–2013	Japan	Reported
Wang et al.	2017	150	SHMT2	IHC	Staining scores with intensity (≥2/2)	36	2012–2013	China	Survival curve
Bernhardt et al.	2017	801	SHMT2	Reverse phase protein arrays	Median expression level	–	2009–2011	Germany	Reported
Miyo et al.	2017	117	SHMT2	IHC	The samples showing an average staining were used as a positive control	58.8	2006–2009	Japan	Survival curve
Zhang et al.	2016	128	SHMT2	IHC	Staining scores with intensity and proportion	Until 30 September 2010	2002–2006	China	Reported
Wu et al.	2016	86	SHMT2	IHC	Staining scores with intensity (≥3/4)	–	–	China	Survival curve

GC, gastric cancer; EC, esophageal cancer; CC, colorectal cancer; SHMT, serine hydroxymethyltransferase; IHC, immunohistochemistry; HR, hazard ratio.