Table 1. Clinical characteristics of the subjects for amino acids metabolism analysis.

Characteristics	Serum sample		Tissue sample
	LSCC	NC	LSCC	ParaLC
No.	20	15	20	19
Sex (male/female)	20/0	15/0	20/0	19/0
Age (years)	62.75 ± 7.83	58.47 ± 4.67	62.8 ± 10.04	63.63 ± 9.58
TNM stage (AJCC 8)
Stage I+II	12	/	10	/
Stage III+IV	8	/	10	/

Note:

AJCC, American joint committee on cancer; T, tumor; N, node; M, metastasis.