. 2020 Mar;8(6):282. doi: 10.21037/atm.2020.03.30

Table 3. Relationship between COL4A1 level and clinicopathologic features (N=33).

Characteristics	No. of Patients		PYGM △Ct^a, mean ± SD	Non-parametric test value	P value
Characteristics	No.	%	PYGM △Ct^a, mean ± SD	Non-parametric test value	P value
Age (years)
<60	10	30.3	28.61±19.99	Z =−1.449	0.147
≥60	23	69.7	19.58±13.11	Z =−1.449	0.147
Gender
Female	10	30.3	18.34±9.70	Z =−0.588	0.557
Male	23	69.7	24.05±17.68	Z =−0.588	0.557
Smoking history
Nonsmoker	21	63.6	19.92±13.03	Z =−1.160	0.246
Smoker	12	36.4	26.51±19.59	Z =−1.160	0.246
Alcohol history
Nondrinker	23	69.7	21.43±18.15	Z =−1.528	0.127
Drinker	10	30.3	24.36±8.43	Z =−1.528	0.127
Tumor size (cm)
≤4	23	69.7	20.04±12.79	Z =−0.666	0.505
>4	10	30.3	26.72±21.28	Z =−0.666	0.505
Lymph node metastasis
pN0	23	69.7	17.32±9.11	Z =−2.350	0.019
pN1 to pN2	10	30.3	33.82±21.65	Z =−2.350	0.019
TNM stage
I-II	17	51.5	16.04±8.21	Z =−2.089	0.037
III-IV	16	48.5	28.99±19.13	Z =−2.089	0.037
Pathological differentiation
Well	30	90.9	22.84±16.13	Z =−0.679	0.497
Moderately/poorly	3	9.1	14.24±0.81	Z =−0.679	0.497
Disease site
Tongue	11	33.3	29.37±19.32	H =0.826	0.520
Gingival	8	24.2	18.50±12.90
Cheek	8	24.2	18.24±16.80
Floor of mouth	2	3.0	22.46±9.62
Oropharynx	4	12.1	19.67±4.82
Recurrence
No	26	78.8	22.37±17.03	Z =−0.264	0.792
Yes	7	21.2	22.15±10.81	Z =−0.264	0.792

SD, standard deviation; pN, pathological lymph node status; TNM stage, tumor-lymph node-metastasis stage. ^a△Ct indicates the difference in the cycle number at which a sample’s fluorescent signal passes a given threshold above baseline (Ct) derived from a specific gene compared with that of β-actin in tumor tissues.