Selection and description of included studies
The preliminary literature search of relevant lncRNA SNHG17 and cancer clinical parameters in PubMed (n= 17), Web of science (n= 33), Embase (n= 14) and Cochrane Library identified 64 publications (Figure 1). Among them, 32 duplicate literatures and 15 articles unrelated to cancer were removed. After reading the full text, 4 articles were removed, including 1 article unrelated to clinical research and 3 articles unable to extract data. A total of 13 articles were finally included in meta-analysis, including gastric cancer[14, 20], hepatocellular carcinoma[15, 16], lung adenocarcinoma cancer[21], colorectal cancer[22, 23], breast cancer[24], prostate cancer[25], Ovarian cancer[26], melanoma[27], tongue squamous cell carcinoma[28], and renal cell carcinoma[18].
The main characteristics of the qualified articles were summarized in Table 1. All included studies were performed in China and published between 2017 and 2022. The expression level of lncRNA SNHG17 was detected by qRT-PCR, and all patients were divided into high expression and low expression groups. All 13 studies, 2 recorded the HR and 95% CI of OS, and the OS data of the other 11 studies were indirectly calculated by Kaplan -Meier curve.
Table 1 The characteristic details of included studies.
Authors
|
Year
|
Country
|
Tumor type
|
Sample size
|
Follow-up months
|
Detection method
|
Survival analysis
|
HR calculation method
|
NOS
|
Chen, L.
|
2019
|
China
|
GC
|
157
|
60
|
qRT-PCR
|
OS PFS
|
K-M
|
8
|
Gao, H.
|
2019
|
China
|
melanoma
|
148
|
60
|
qRT-PCR
|
OS
|
K-M
|
7
|
Pan, X.
|
2020
|
China
|
Ovarian cancer
|
90
|
100
|
qRT-PCR
|
OS
|
K-M
|
7
|
Du Y
|
2020
|
China
|
BRCA
|
58
|
60
|
qRT-PCR
|
OS
|
K-M
|
6
|
Ma, Z
|
2017
|
China
|
colorectal cancer
|
56
|
40
|
qRT-PCR
|
OS
|
K-M
|
7
|
Liu, X
|
2020
|
China
|
TSCC
|
56
|
60
|
qRT-PCR
|
OS
|
K-M
|
8
|
Luo, Y.
|
2021
|
China
|
HCC
|
364
|
120
|
qRT-PCR
|
OS DFS
|
K-M
|
8
|
Zhang, Z
|
2021
|
China
|
LUAD
|
50
|
150
|
qRT-PCR
|
OS
|
K-M
|
7
|
Wu, J
|
2021
|
China
|
RCC
|
84
|
120
|
qRT-PCR
|
OS RFS
|
Directly
|
7
|
Zhu, X.
|
2021
|
China
|
HCC
|
58
|
60
|
qRT-PCR
|
OS
|
Directly
|
7
|
Zhao, H
|
2021
|
China
|
prostate cancer
|
58)
|
70
|
qRT-PCR
|
OS
|
K-M
|
6
|
Bian, Z.
|
2021
|
China
|
colorectal cancer
|
214
|
180
|
qRT-PCR
|
OS DFS
|
K-M
|
8
|
ZHANG, X
|
2021
|
China
|
GC
|
99
|
80
|
qRT-PCR
|
OS
|
K-M
|
7
|
Tags: GC: gastric cancer, BRCA: breast cancer, TSCC: tongue squamous cell carcinoma, LUAD: lung adenocarcinoma, RCC: renal cell carcinoma, HCC: hepatocellular carcinoma.
Association of SNHG17 expression with OS
Thirteen studies were included in the meta-analysis of OS[14-16, 18, 20-28]. As shown in Figure 2A, a fixed effect model was adopted because there was no heterogeneity (I2 = 0%, P=0.97) in the included studies. The results indicated that the patients with high expression of lncRNA SNHG17 was closely related to the shorter OS of patients (HR = 1.78, 95%CI = 1.50-2.10, P < 0.01). Besides, we performed subgroup analysis based on cancer type (Figure 2B) sample size (Figure 2C), and follow-up time (Figure 2D), showing that SNHG17 expression levels correlated with the prognosis of cancer patients, with high expression predicting poorer OS, which further validates our results. More details can be found in in Table 2.
Table 2: The results of subgroup analyses of OS.
Subgroup
|
Studies
|
HR and 95%CI
|
P
|
I2
|
Model
|
Sample size
|
13
|
1.78(1.50-2.10)
|
0.97
|
0
|
Fixed
|
<90
|
7
|
2.04(1.49-2.80)
|
0.99
|
0
|
Fixed
|
≥90
|
6
|
1.69(1.39-2.05)
|
0.75
|
0
|
Fixed
|
Cancer type
|
13
|
1.78(1.50-2.10)
|
0.97
|
0
|
Fixed
|
Colorectal cancer
|
2
|
2.14(1.24-3.68)
|
0.99
|
0
|
Fixed
|
Gastric cancer
|
2
|
2.00(1.35-2.97)
|
0.50
|
0
|
Fixed
|
Hepatocellular carcinoma
|
2
|
1.60(1.23-2.06)
|
0.52
|
0
|
Fixed
|
Other
|
7
|
1.82(1.35-2.46)
|
0.97
|
0
|
Fixed
|
Follow-up months
|
13
|
1.78(1.50-2.10)
|
0.97
|
0
|
Fixed
|
≤60
|
7
|
1.79(1.45-2.21)
|
0.78
|
0
|
Fixed
|
>60
|
6
|
1.76(1.31-2.31)
|
0.94
|
0
|
Fixed
|
Association of SNHG17 expression with DFS, RFS and PFS
See Figure 3 for illustration, among all the included studies, two articles introduced DFS[15, 23], and one article reported PFS[20] and RFS[18] respectively, which were included into meta-analysis. The results showed that the DFS (HR = 1.36, 95%CI = 1.06-1.74, P < 0.05, I2=0%), RFS (R = 2.49,95%CI = 1.13-5.49, P < 0.01) and PFS (R = 2.02, 95%CI = 1.24–3.28, P < 0.05) of cancer patients with high expression of lncRNA SNHG17 were significantly shorter (Figure 3A). The funnel plot means that there is no obvious bias (Figure 3B).
Association of SNHG17 expression with clinical characteristics
The clinical data of 10 articles were extracted and included in meta-analysis[14, 16, 20-22, 24-28].The correlation between age, gender, tumor size, clinical stage, LNM, distant metastasis and differentiation and SNHG17 expression was analyzed. As listed in Table 3, there was no distinct relationship between lncRNA SNHG17 expression and age (P = 0.84),gender (P = 0.28) and tumor size (P =0.47) (Supplement Figure 1(A-C)). However, high lncRNA SNHG17 expression was significantly related to advanced clinical stage (HR = 3.25, 95%CI = 1.77-5.97, P < 0.01) (Figure 4A), earlier lymph node metastasis (HR = 2.94, 95%CI = 2.15-4.02, P < 0.01) (Figure 4B), worse differentiation (HR = 1.41, 95%CI = 0.82-2.45, P < 0.01) (Figure 4C) and earlier metastasis (HR = 2.33, 95%CI = 1.30-4.19, P < 0.01) (Figure 4D).
Table 3: Meta analysis of the relationship between the expression of SNHG17 and clinical parameters.
Subgroup
|
studies
|
participants
|
OR and 95%CI
|
P
|
I2
|
Model
|
Age (old vs young)
|
10
|
830
|
1.26(0.94-1.69)
|
0.84
|
0
|
Fixed
|
Gender (male vs female)
|
7
|
598
|
1.20(0.86-1.69)
|
0.28
|
0
|
Fixed
|
Tumor size (large vs small)
|
8
|
533
|
2.80(1.94-4.05)
|
0.47
|
0
|
Fixed
|
Clinical stages(Ⅲ/Ⅳ vs Ⅰ/Ⅱ)
|
10
|
830
|
3.25(1.77-5.97)
|
0.0002
|
72
|
Random
|
LNM(yes vs no)
|
9
|
780
|
2.94(2.15-4.02)
|
0.00001
|
0
|
Fixed
|
Differentiation(poor vs good)
|
2
|
215
|
1.41(0.82-2.45)
|
0.22
|
16
|
Fixed
|
Metastasis(yes vs no)
|
2
|
215
|
2.33(1.30-4.19)
|
0.005
|
21
|
Fixed
|
SNHG17 expression in TCGA pan-cancer dataset
TCGA pan-cancer dataset was explored to further verified our conclusions. SNHG17 aberrant expression in cancer tissue were found in Cholangiocarcinoma (CHOL), colon adenocarcinoma (COAD), Lymphoid Neoplasm Diffuse Large B-cell Lymphoma (DLBC), Glioblastoma multiforme (GBM), Brain Lower Grade Glioma (LGG), Pancreatic adenocarcinoma (PAAD), Rectum adenocarcinoma (READ), Testicular Germ Cell Tumors (TGCT), Thymoma (THYM) and Stomach adenocarcinoma (STAD). (Figure 5(A-J)). Furthermore, K-M survival curves suggested that high SNHG17 expression was associated with poorer OS and DFS. (Figure 5(K-L)), in which indicated that SNHG17 could be a novel prognostic biomarker for human multiple cancers.
Publication bias and sensitivity analysis
The absence of publication bias in the 13 papers included was demonstrated by funnel plots as well as the begg's test. The funnel plots were clearly symmetrical and begg's test (P = 0.200) also showed no publication bias (Figure 6A). Sensitivity analysis confirmed the robustness of the obtained results (Figure 6B).