The associations between SOCS6 expression and clinicopathological variables
After accomplishing immunohistochemical staining, we could find that SOCS6 was mainly distributed in cytoplasm and nucleus. Of the 255 GIST patients, 102 ones were identified to have high SOCS6 and 153 ones low SOCS6 expression. The associations between SOCS6 expression and clinicopathological variables were presented in Table 1, from which we could see that SOCS6 expression was significantly associated with tumor size (P = 0.001). However, SOCS6 expression was not significantly correlated with other variables including age, gender, tumor location, necrosis of tumor, mitotic index and NIH risk grade.
Table 1
Associations between SOCS6 expression and clinicopathological variables.
|
High expression
(N = 102)
|
Low expression
(N = 153)
|
P
|
Age
|
54.45 ± 12.70
|
56.42 ± 12.28
|
0.22
|
Gender
|
|
|
0.44
|
Male
|
55(53.9%)
|
91(59.5%)
|
|
Female
|
47(46.1%)
|
62(40.5%)
|
|
Tumor location
|
|
|
0.48
|
Stomach
|
66(64.7%)
|
94(61.4%)
|
|
Small intestine
|
31(33.3%)
|
51(33.3%)
|
|
Colorectum
|
2(2.0%)
|
8(5.2%)
|
|
Tumor size(cm)
|
4.97 ± 4.13
|
7.86 ± 6.05
|
0.001
|
Necrosis of tumor
|
|
|
0.58
|
No
|
73(71.6%)
|
104(68.0%)
|
|
Yes
|
29(28.4%)
|
49(32.0%)
|
|
Mitotic index
|
|
|
0.48
|
<5%
|
65(63.7%)
|
92(60.1%)
|
|
5%~10%
|
20(19.6%)
|
26(17.0%)
|
|
>10%
|
17(16.7%)
|
35(22.9%)
|
|
NIH risk grade
|
|
|
0.70
|
Extremely low
|
12(11.8%)
|
12(7.8%)
|
|
Low
|
28(27.5%)
|
39(25.5%)
|
|
Moderate
|
21(20.6%)
|
35(22.9%)
|
|
High
|
41(40.2%)
|
67(43.8%)
|
|
The impacts of SOCS6 on OS
The follow-ups of the 255 GIST patients range from 2 to 156 months and the 1-year, 3-year and 5-year OS of these 255 patients were 96.81%, 92% and 83.1% respectively. The mean survival time of 255 patients was 119.82 ± 4.38 months. For patients with high SOCS6 expression, the 1-year, 3-year and 5-year OS were 97.79%, 95.75% and 89.62% respectively and the mean survival was 135.00 ± 5.30 months. Whereas, for patients with low SOCS6 expression, the 1-year, 3-year and 5-year OS were 96.04%, 89.49% and 78.95% respectively and the mean survival was 95.56 ± 4.56 months. According to Kaplan-Meier curve analysis, low SOCS6 expression (P = 0.0059), tumor size > 5cm (P < 0.001), necrosis of tumor (P < 0.001), Mitotic index > 5/50HPF(P = 0.0001), moderate or high NIH risk grade (P < 0.001) were significantly associated with worse OS of GIST patients (shown in Fig. 2a to Fig. 2e). Then it was revealed by univariate Cox proportional hazard regression model analysis that tumor size (P < 0.001, HR = 3.67, 95%CI: 1.99~6.74), necorsis of tumor (P < 0.001, HR = 4.50, 95%CI:2.48~8.18), mitotic index (P < 0.001, HR = 3.13, 95%CI: 1.75~5.62), moderate or high NIH risk grade (P < 0.001, HR = 7.37, 95%CI: 2.90~18.73) and low SOCS6 expression (P = 0.008, HR = 2.51, 95%CI: 1.27~4.93) were significantly associated with OS of GIST patients (shown in Table 2). Subsequently, tumor size (P = 0.007, HR = 2.49, 95%CI: 1.27~4.56), necorsis of tumor (P = 0.001, HR = 3.03, 95%CI: 1.54~5.95), mitotic index (P = 0.023, HR = 2.11, 95%CI: 1.11~4.02), and low SOCS6 expression (P = 0.009, HR = 2.58, 95%CI: 1.27~5.24) were demonstrated by multivariate Cox proportional hazard regression model analysis to be independent predictive factors for OS (shown in Table 2).
Table 2
Cox proportional-hazard regression model analysis for overall survival.
|
|
Univariate
|
Multivariate
|
|
3-year OS
|
5-year OS
|
HR(95%CI)
|
P
|
HR(95%CI)
|
P
|
Age(years)
|
|
|
|
|
|
|
≤ 65
|
92.43%
|
83.68%
|
reference
|
|
reference
|
|
>65
|
90.58%
|
81.88%
|
1.32(0.70~2.46)
|
0.390
|
1.54(0.81~2.93)
|
0.187
|
Gender
|
|
|
|
|
|
|
Male
|
89.77%
|
80.46%
|
reference
|
|
reference
|
|
Female
|
95.01%
|
86.78%
|
0.64(0.35~1.16)
|
0.141
|
0.61(0.32~1.12)
|
0.115
|
Tumor location
|
|
|
|
|
|
|
Stomach
|
91.14%
|
86.00%
|
reference
|
|
reference
|
|
Non-stomach
|
93.43%
|
78.49%
|
1.75(0.98~3.11)
|
0.058
|
1.20(0.66~2.20)
|
0.550
|
Tumor size(cm)
|
|
|
|
|
|
|
≤5
|
96.17%
|
90.07%
|
reference
|
|
reference
|
|
>5
|
86.41%
|
73.38%
|
3.67(1.99~6.74)
|
< 0.001
|
2.40(1.27~4.56)
|
0.007
|
Necrosis of tumor
|
|
|
|
|
|
|
No
|
96.39%
|
91.67%
|
reference
|
|
reference
|
|
Yes
|
82.47%
|
66.62%
|
4.50(2.48~8.18)
|
< 0.001
|
3.03(1.54~5.95)
|
0.001
|
Mitotic index
|
|
|
|
|
|
|
≤5%
|
96.47%
|
89.78%
|
reference
|
|
reference
|
|
>5%
|
84.74%
|
72.18%
|
3.13(1.75~5.62)
|
< 0.001
|
2.11(1.11~4.02)
|
0.023
|
NIH risk grade
|
|
|
|
|
|
|
Extremely low or low
|
100%
|
100%
|
reference
|
|
|
|
Moderate or high
|
87.41%
|
72.60%
|
7.37(2.90~18.73)
|
< 0.001
|
|
|
SOCS6 expression
|
|
|
|
|
|
|
High
|
95.75%
|
89.62%
|
reference
|
|
reference
|
|
Low
|
89.49%
|
78.95%
|
2.51(1.27~4.93)
|
0.008
|
2.58(1.27~5.24)
|
0.009
|
The impacts of SOCS6 expression on RFS
The 1-year, 3-year and 5-year RFS of these 255 patients were 95.21%, 89.30% and 77.98% respectively. The median RFS of 255 patients was 114.02 ± 4.61 months. For patients with high SOCS6 expression, the 1-year, 3-year and 5-year RFS were 96.96%, 94.81% and 84.79% respectively and the mean RFS was 129.49 ± 5.73 months. Whereas, for patients with low SOCS6 expression, the 1-year, 3-year and 5-year RFS were 93.36%, 85.62% and 73.30% respectively and the mean RFS was 91.27 ± 4.64 months. According to Kaplan-Meier curve analysis, low SOCS6 expression (P = 0.0071), non-stomach GIST (P = 0.0107), tumor size > 5cm (P < 0.001), necrosis of tumor (P < 0.001), Mitotic index > 5/50HPF(P < 0.001), moderate or high NIH risk grade (P < 0.001) were significantly associated with worse RFS of GIST patients (shown in Fig. 3a to Fig. 3f). Then it was revealed by univariate Cox proportional hazard regression model analysis that tumor size (P < 0.001, HR = 3.18, 95%CI: 1.84~5.50), tumor location (P = 0.012, HR = 1.95, 95%CI: 1.16~3.30), necorsis of tumor (P < 0.001, HR = 3.93, 95%CI:2.31~6.68), mitotic index (P < 0.001, HR = 2.93, 95%CI: 1.73~4.97), moderate or high NIH risk grade (P < 0.001, HR = 8.89, 95%CI: 3.53~22.36) and low SOCS6 expression (P = 0.009, HR = 2.20, 95%CI: 1.22~3.98) were significantly associated with RFS of GIST patients (shown in Table 3). Subsequently, tumor size (P = 0.014, HR = 2.06, 95%CI: 1.16~3.68), necorsis of tumor (P = 0.002, HR = 2.60, 95%CI: 1.44~4.71), mitotic index (P = 0.020, HR = 2.60, 95%CI: 1.44~4.71), and low SOCS6 expression (P = 0.018, HR = 2.10, 95%CI: 1.14~3.89) were demonstrated by multivariate Cox proportional hazard regression model analysis to be independent predictive factors for RFS (shown in Table 3).
Table 3
Cox proportional-hazard regression model analysis for for recurrence-free survival
|
|
Univariate
|
Multivariate
|
|
3-year RFS
|
5-year RFS
|
HR(95%CI)
|
P
|
HR(95%CI)
|
P
|
Age (years)
|
|
|
|
|
|
|
≤ 65
|
89.50%
|
78.77%
|
reference
|
|
reference
|
|
>65
|
88.72%
|
75.62%
|
1.25(0.70~2.23)
|
0.452
|
1.41(0.78~2.53)
|
0.255
|
Gender
|
|
|
|
|
|
|
Male
|
87.8%
|
75.60%
|
reference
|
|
reference
|
|
Female
|
91.32%
|
80.87%
|
0.69(0.40~1.18)
|
0.181
|
0.72(0.41~1.25)
|
0.243
|
Tumor location
|
|
|
|
|
|
|
Stomach
|
90.78%
|
81.16%
|
reference
|
|
reference
|
|
Non-stomach
|
86.79%
|
72.53%
|
1.95(1.16~3.30)
|
0.012
|
1.46(0.85~2.52)
|
0.171
|
Tumor size(cm)
|
|
|
|
|
|
|
≤5
|
94.86%
|
86.26%
|
reference
|
|
reference
|
|
>5
|
81.77%
|
65.76%
|
3.18(1.84~5.50)
|
< 0.001
|
2.06(1.16~3.68)
|
0.014
|
Necrosis of tumor
|
|
|
|
|
|
|
No
|
94.63%
|
87.28%
|
reference
|
|
reference
|
|
Yes
|
77.49%
|
58.83%
|
3.93(2.31~6.68)
|
< 0.001
|
2.60(1.44~4.71)
|
0.002
|
Mitotic index
|
|
|
|
|
|
|
≤5%
|
95.35%
|
87.26%
|
reference
|
|
reference
|
|
>5%
|
79.41%
|
62.15%
|
2.93(1.73~4.97)
|
< 0.001
|
1.99(1.11~3.55)
|
0.020
|
NIH risk grade
|
|
|
|
|
|
|
Extremely low or low
|
98.89%
|
98.89%
|
reference
|
|
|
|
Moderate or high
|
83.85%
|
64.90%
|
8.89(3.53~22.36)
|
< 0.001
|
|
|
SOCS6 expression
|
|
|
|
|
|
|
High
|
94.81%
|
84.79%
|
reference
|
|
reference
|
|
Low
|
85.62%
|
73.30%
|
2.20(1.22~3.98)
|
0.009
|
2.10(1.14~3.89)
|
0.018
|