Early gastric cancer frequently has high expression of KK-LC-1, a cancer-testis antigen

Table 1 Cancer-testis antigen expression in 83 patients with gastric cancer

CTA	Positive	Negative	Proportion (%)
KK-LC-1	66	17	79.5
MAGE-A1	27	56	32.5
MAGE-A3	33	50	39.7
NY-ESO-1	13	70	15.7

CTA: Cancer-testis antigen; KK-LC-1: Kita-Kyushu lung cancer antigen-1; MAGE: Melanoma antigen; NY-ESO-1: New York esophageal cancer-1.

Table 2 Correlation between CTAs and clinicopathological factors n (%)

Characteristics	The expression number of each CTA
	KK-LC-1	MAGE-A1	MAGE-A3	NY-ESO-1
Age (yr) (mean ± SD)	P = 0.944	P = 0.104	P = 0.009	P = 0.042
Positive	69.8 ± 11.4 (n = 66)	72.7 ± 7.9 (n = 27)	73.7 ± 7.1 (n = 33)	75.5 ± 7.2 (n = 13)
Negative	70.1 ± 9.5 (n = 17)	68.5 ± 12.0 (n = 56)	67.4 ± 12.3 (n = 50)	68.8 ± 11.2 (n = 70)
Tumor size (mm) (mean ± SD)	P = 0.5202	P = 0.4752	P = 0.862	P = 0.831
Positive	59.9 ± 4.2 (n = 65)	62.5 ± 6.6 (n = 27)	57.9 ± 5.9 (n = 33)	60.5 ± 9.5 (n = 13)
Negative	53.8 ± 8.5 (n = 16)	56.8 ± 4.6 (n = 54)	59.2 ± 4.9 (n = 48)	58.3 ± 4.1 (n = 68)
Gender	P = 0.406	P = 1	P = 0.645	P = 0.758
Male (n = 52)	43 (82.7)	17 (32.7)	22 (42.3)	9 (17.3)
Female (n = 31)	23 (74.2)	10 (32.3)	11 (35.5)	4 (12.9)
Macroscopic type	P = 0.591	P = 1	P = 0.649	P = 1
Localized (n = 49)	40 (81.6)	16 (32.7)	18 (36.7)	8 (16.3)
Infiltrated (n = 34)	26 (76.5)	11 (32.4)	15 (44.1)	5 (14.7)
Histological type	P = 0.599	P = 0.246	P = 1	P = 1
Differentiated (n = 44)	36 (81.8)	17 (38.6)	18 (40.9)	7 (15.9)
Undefferentiated (n = 39)	30 (76.9)	10 (25.6)	15 (38.5)	6 (15.4)
Depth of invasion	P = 0.269	P = 0.089	P = 0.243	P = 0.761
T1 (n = 30)	26 (86.7)	6 (20.0)	9 (30.0)	4 (13.3)
Intramucosal (n = 11)	11 (100)	0 (0)	2 (18.2)	1 (9.1)
Submucosal 1 (n = 5)	4 (80.0)	2 (40.0)	3 (60.0)	1 (20.0)
Submucosal 2 (n = 14)	11 (78.6)	4 (28.6)	4 (28.6)	2 (14.3)
T2-T4 (n = 53)	40 (75.5)	21 (39.6)	24 (45.3)	9 (17.0)
Lymph node metastasis	P = 1	P = 0.17	P = 0.823	P = 1
Negative (n = 40)	32 (80.0)	10 (25.0)	15 (37.5)	6 (15.0)
Positive (n = 43)	34 (79.1)	17 (39.5)	18 (41.9)	7 (16.3)
Lymphatic invasion	P = 1	P = 0.034	P = 0.022	P = 0.498
Negative (n = 22)	18 (81.8)	3 (13.6)	4 (18.2)	2 (9.1)
Positive (n = 61)	48 (78.7)	24 (39.3)	29 (47.5)	11 (18.0)
Venous invasion	P = 0.583	P = 0.028	P = 0.035	P = 0.121
Negative (n = 30)	25 (83.3)	5 (16.7)	7 (23.3)	2 (6.7)
Positive (n = 53)	41 (77.4)	22 (41.5)	26 (49.1)	11 (20.8)
Stage	P = 1	P = 0.162	P = 0.044	P = 0.222
Early (I) (n = 34)	27 (79.4)	8 (23.5)	9 (26.5)	3 (8.8)
Advanced (II-IV) (n = 49)	39 (79.6)	19 (38.8)	24 (49.0)	10 (20.4)
II (n = 21)	16 (76.2)	7 (33.3)	11 (52.4)	3 (14.3)
III (n = 15)	11 (73.3)	7 (46.7)	7 (46.7)	3 (20.0)
IV (n = 13)	12 (92.3)	5 (38.5)	6 (46.2)	4 (30.8)

KK-LC-1: Kita-Kyushu lung cancer antigen-1; MAGE: Melanoma antigen; NY-ESO-1: New York esophageal cancer-1.