Table 3. Kaplan-Meier survival analysis according to SHMT2, MTHFD1 and TYMS protein expression levels in AC, SQCLC and SCLC patients.

Tumor type	SHMT2					MTHFD1					TYMS
	Negative	Weak	Strong	P		Negative	Weak	Strong	P		Negative	Weak	Strong	P
AC (months)	43	32	40	0.06		–	43	35	0.49		40	35	44	0.28
SQCLC (months)	33	23	29	0.42		22	29	31	0.98		33	33	22	0.34
SCLC (months)	9	34	58	0.92		58	50	27	0.96		–	58	24	0.47

SHMT2, serine hydroxymethyltransferase 2; MTHFD1, methylene tetrahydrofolate 1; TYMS, thymidylate synthase; AC, pulmonary adenocarcinoma; SQCLC, squamous cell lung cancer; SCLC, small cell lung cancer.