Study selection and characteristics of included studies
The search strategy was used to retrieve 335 records, including 20 articles from PubMed, 40 from Embase, 41 from Web of science, 1 from Scopus, 18 from Medline in English database, 19 from CNKI and 196 from Wangfang database records in Chinese database. After removing duplicates records, reviews, and letters, there were 179 articles remained. And we browsed and screened the titles and abstracts of the remained articles, then excluded 139 irrelevant studies. After evaluating the full text of the remaining 40 articles, 30 articles related to cell or animal studies which did not contain the diagnostic or prognostic data, as well as 2 studies with incomplete clinical data, were excluded, and only 8 studies were included in the systematic review and meta-analysis, including 629 cancer patients (Figure1).
We analyzed in 559 patients from 7 studies to evaluate the pooled diagnostic indicators and diagnostic value of miR-525 in different cancers and the association between high/low expression level of miR-525 and different clinical characteristics of cancer patients[21–27]. And the pooled prognostic analysis of the predictive value of low expression levels of miR-525 in survival outcomes in cancer patients was conducted in 324 patients from 3 studies[26–28]. The characteristics of the literatures included in the diagnostic meta-analysis were summarized in Table1, while detailed information about the literatures included in the prognostic meta-analysis could be seen in Table2. These studies were conducted from 2013 to 2023, with one in the Czech Republic, one in Turkey and six in China[21–28]. These selected studies have included various types of cancer: hepatocellular carcinoma (HCC, n=1), colorectal cancer (COAD, n=1), breast cancer (BC, n=1), gestational trophoblastic tumor (GTT, n=1), Burkitt lymphoma (BL, n=1), Hodgkin's lymphoma (HL, n=1), diffuse large B-cell lymphoma (DLBCL, n=1), and thymoma and thymic carcinoma (THYM, n=1)[21–28]. Different assay methods (TaqMan or SYBR) were used to detect miR-525 expression in tissues (n=7) and serum (n=1) by RT-qPCR[21–28]. Two studies in the diagnostic meta-analysis involved miR-525-3p and five involved miR-525-5p, while three studies in the prognostic meta-analysis were all related to miR-525-5p[21–28]. The included studies were classified according to the miR-525 expression, three studies in the diagnostic meta-analysis involved high miR-525 expression in cancer patients and four involved low expression of miR-525, while all studies included in the prognostic meta-analysis had low expression of miR-525[21–28].
Table 1: Main characteristics of the eligible studies for diagnostic meta-analysis
Author
|
Country/year
|
MiR-525 type
|
Cancer type
|
Specimen
|
Test Method
|
Expression
Status
|
Patients
(control)
|
TP
|
FP
|
FN
|
TN
|
SEN
(%)
|
SEP
(%)
|
PLR
|
NLR
|
DOR
|
QUADAS-2
|
Fei Pang
|
China/2013
|
miR-525-3p
|
HCC
|
Tissue
|
RT-qPCR
|
Up-regulated
|
136
|
80
|
2
|
47
|
7
|
63
|
78
|
2.83
|
0.48
|
5.96
|
7
|
Guo-Zhen Wang
|
China/2023
|
miR-525-5p
|
COAD
|
Tissue
|
RT-qPCR
|
Up-regulated
|
68(50)
|
24
|
26
|
8
|
61
|
75
|
70
|
2.51
|
0.36
|
7.04
|
11
|
Hui-Hua Tang
|
China/2023
|
miR-525-5p
|
BC
|
|
RT-qPCR
|
Down-regulated
|
180
|
38
|
14
|
10
|
118
|
79
|
89
|
7.46
|
0.23
|
32.03
|
10
|
Ilona Hromadnikova
|
Czech Republic/2017
|
miR-525-5p
|
GTT
|
Plasma
|
RT-qPCR
|
Up-regulated
|
60(38)
|
39
|
3
|
0
|
35
|
100
|
92
|
11.00
|
0.01
|
801.29
|
11
|
Qing-Qing Wang
|
China/2021
|
miR-525-5p
|
BL
|
Tissue
|
RT-qPCR
|
Down-regulated
|
9(25)
|
8
|
5
|
1
|
20
|
89
|
80
|
4.44
|
0.14
|
32.00
|
10
|
Semra Paydas
|
Turkey/2016
|
miR-525-3p
|
HL
|
Tissue
|
RT-qPCR
|
Down-regulated
|
32(60)
|
26
|
47
|
6
|
13
|
81
|
22
|
1.04
|
0.87
|
1.20
|
10
|
Ting Zhao
|
China/2020
|
miR-525-5p
|
DLBCL
|
Tissue
|
RT-qPCR
|
Down-regulated
|
74(30)
|
55
|
5
|
19
|
25
|
74
|
83
|
4.46
|
0.31
|
14.47
|
11
|
Abbreviation: HCC, hepatocellular carcinoma; COAD, colorectal cancer; BC, breast cancer; GTT, gestational trophoblastic tumor; BL, Burkitt lymphoma; HL, Hodgkin's lymphoma; DLBCL, diffuse large B-cell lymphoma; THYM, thymoma and thymic carcinoma; RT-qPCR, quantitative real-time polymerase chain reaction.
Table 2: Main characteristics of the eligible studies for prognostic meta-analysis
Author
|
Country/year
|
MiR-525 type
|
Expression
Status
|
Cancer type
|
Specimen
|
Test Method
|
Patients
|
Follow-up Period (month)
|
Survival Result
|
HR (95%CI)
|
Hui-Hua Tang
|
China/2023
|
miR-525-5p
|
Down-regulated
|
BC
|
Tissue
|
RT-qPCR
|
180
|
60
|
RFS
OS
|
0.13(0.02~0.78)
|
Jin Wang
|
China/2021
|
miR-525-5p
|
Down-regulated
|
THYM
|
Tissue
|
RT-qPCR
|
70
|
60
|
OS
|
0.31(0.05~2.09)
|
Ting Zhao
|
China/2020
|
miR-525-5p
|
Down-regulated
|
DLBCL
|
Tissue
|
RT-qPCR
|
74
|
180
|
OS
|
0.14(0.04~0.49)
|
Abbreviation: BC, breast cancer; THYM, thymoma and thymic carcinoma; DLBCL, diffuse large B-cell lymphoma; HR, hazard ratio; RFS, recurrence free survival; OS, overall survival.
Table 3: Newcastle–Ottawa quality assessment scale
Author
|
Year
|
Quality indicators from Newcastle-Ottawa Scale
|
Score
|
|
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
|
Jin Wang
|
2021
|
★
|
★
|
★
|
★
|
﹣
|
★
|
★
|
★
|
7
|
Hui-Hua Tang
|
2023
|
★
|
★
|
★
|
★
|
﹣
|
★
|
★
|
★
|
7
|
Ting Zhao
|
2020
|
★
|
★
|
★
|
★
|
★
|
★
|
★
|
★
|
8
|
1.Representativeness of the exposed cohort; 2. Selection of the nonexposed cohort; 3. Ascertainment of exposure; 4. Demonstration that outcome of interest was not present at start of study; 5. Comparability of cohorts on the basis of the design or analysis; 6. Assessment of outcome; 7. Was follow-up long enough for outcomes to occur; 8. Adequacy of follow up of cohorts. Note: ★ and ★★ means the studies are satisfied one or two criterions below the tables
Quality assessment:
We assessed the quality of the studies included in the diagnostic meta-analysis using the QUADAS-2 tool[19]. All the studies were scored between 7 and 11, indicating that the studies included in the meta-analysis were of medium or high quality, as shown in Table 1 and FigureS1 and S2 in Additional File 2. For the prognostic meta-analysis, we used the Newcastle-Ottawa Scale (NOS) tool[20], and all the studies scored 7 to 8 points, indicating that the included studies were of high quality, as shown in Table 3.
Results of the diagnostic meta-analysis:
The results of the diagnostic meta-analysis of the 7 included studies are illustrated in the forest plots as shown in Figure 2 and Table 1 by using the random-effects model[21–27]. The pooled sensitivity (SEN), specificity (SPE), and diagnostic odds ratio (DOR) were shown in Table 1 as follows: 0.75 (95%CI = 0.7-0.79), 0.73 (95%CI = 0.68-0.78), and 13.08 (95%CI = 4.18-40.91), and the pooled positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 3.74 (95%CI = 1.53-9.13) and 0.33 (95%CI = 0.20-0.55), respectively (Figure2A-E). And the ROC and SROC curve were shown as an untypical ‘shoulder-arm’ pattern which means no significant threshold effect existed in the current meta-analysis, with the AUC under SROC was 0.86 (95%CI = 0.83-0.89) (Figure2F-G). The pooled meta-analysis results suggested that miR-525 had high diagnostic accuracy, in which the pooled sensitivity was 0.75, the specificity was 0.73, and AUC was 0.86 close to 1, and the Youden index was 0.48. We used Fagan’s nomogram to assess the clinical utility of the index test (Figure3A). In the Fagan plot, the prior probability was 20%, the posterior-positive probability (PPP) was 47%, the posterior-negative probability (PPN) was 6%, and LR+ was 4, and LR- was 0.29. And the larger the LR+ was, the stronger the detection capability of miR-525 as a diagnostic marker, while the smaller the LR-, the stronger the ability of the test biomarker to exclude the disease. While the likelihood ratio in the Likelihood Ratio Scattergram is greater than 0.1 and less than 10 (Figure3B). Taken together, miR-525 had a preferable accuracy as a diagnostic identification marker for cancer patients.
The significant heterogeneity was found among the included studies of diagnostic meta-analysis, shown as follows: sensitivity (I2=82.2, p-value=0.00), specificity (I2 = 94.1, p-value=0.00), PLR (I2 = 95, p-value=0.00), NLR (I2 = 71.4, p-value=0.00), and DOR (I2 = 81.3, p-value < 0.01). This result suggests that the diagnostic efficacy of miR-525 needs further analysis to explain the source of heterogeneity. To account for potential sources of heterogeneity, we also performed sensitivity analyses and subgroup analyses, and explored the relationship between miR-525 and patient clinical characteristics.
Subgroup analysis of diagnostic value of miR-525 in various cancers:
Since the meta-analysis of diagnosis and prognosis in our study included less than 10 articles, multivariate-meta-regression could not be performed, and only subgroup analysis could be used to explore the source of heterogeneity in meta-analysis. The results of a subgroup analysis of the diagnostic performance of miR-525 are summarized in Table 4 and FigureS3 in Additional File 2. MiR-525 showed good diagnostic accuracy when the TMN stage of cancer was early, such as stage I-II with SEN = 0.89(0.80-0.94), and SPE = 0.90(0.84-0.94). For ethnicity, it showed high diagnostic efficacy in Asian populations with SEN = 0.74(0.68-0.79), SPE = 0.58(0.50-0.67), and AUC = 0.84(0.83-0.85), but the higher sensitivity to cancer diagnosis in Caucasian populations with SEN = 0.92(0.83-0.97), and SPE = 0.49(0.99-0.59). For different subtypes of miR-525, compared with miR-525-3p (SEN = 0.67(0.59-0.74), SPE = 0.29(0.19-0.41)), the accuracy of miR-525-5p for cancer diagnosis was higher (SEN = 0.81(0.75-0.86), SPE 0.83 = (0.78-0.87), AUC = 0.90(0.83-0.97)). Compared studies publication in the year of pre-2020 (SEN = 0.74(0.68~0.79), SPE = 0.58(0.50~0.67), AUC = 0.85(0.83~0.87)), in the literature published after 2020, miR-525 has a better diagnostic value in cancers (SEN = 0.79(0.69-0.87), SPE = 0.82(0.76-0.86), AUC = 0.87(0.84-0.90)).
Table 4: Subgroup analysis of the diagnostic value of the miR-525 in various cancers.
Sub-group
|
|
N of studies
|
SEN (95%CI)
|
SPE (95%CI)
|
PLR (95%CI)
|
NLR (95%CI)
|
DOR (95%CI)
|
AUC (95%CI)
|
Publication year
|
≤2020
|
4
|
0.74(0.68~0.79)
|
0.58(0.50~0.67)
|
3.23(0.61~16.95)
|
0.38(0.16~0.89)
|
10.79(1.53~76.17)
|
0.85(0.83~0.87)
|
>2020
|
3
|
0.79(0.69~0.87)
|
0.82(0.76~0.86)
|
4.10(1.94~8.67)
|
0.28(0.19~0.42)
|
15.40(5.12~46.34)
|
0.87(0.84~0.90)
|
Ethnicity
|
Asian
|
5
|
0.74(0.68~0.79)
|
0.58(0.50~0.67)
|
3.23(0.61~16.95)
|
0.38(0.16~0.89)
|
10.79(1.53~76.17)
|
0.84(0.83~0.85)
|
Caucasian
|
2
|
0.92(0.83~0.97)
|
0.49(0.39~0.59)
|
3.29(0.10~109.42)
|
0.12(0.00~39.99)
|
26.87(0.02~34244.93)
|
/
|
Cancer types
|
Female Reproductive System Tumor
|
2
|
0.89(0.80~0.94)
|
0.90(0.84~0.94)
|
7.86(5.00~12.36)
|
0.07(0.00~1.79)
|
114.66(4.26~3085.33)
|
/
|
Lymphoma
|
3
|
0.77(0.69~0.85)
|
0.50(0.41~0.60)
|
2.51(0.63~10.03)
|
0.41(0.81~0.91)
|
6.27(0.96~40.88)
|
0.84(0.80~0.88)
|
Digestive System Cancer
|
2
|
0.65(0.57~0.73)
|
0.71(0.61~0.80)
|
2.47(1.73~3.53)
|
0.45(0.32~0.63)
|
6.21(2.87~13.41)
|
/
|
TNM stage
|
(I-II)
|
2
|
0.89(0.80~0.94)
|
0.90(0.84~0.94)
|
7.86(5.00~12.36)
|
0.07(0.00~1.79)
|
114.66(4.26~3085.33)
|
/
|
(II-III)
|
2
|
0.65(0.56~0.73)
|
0.79(0.62~0.91)
|
3.87(1.96~7.65)
|
0.30(0.05~1.90)
|
11.22(2.27~55.38)
|
/
|
(III-IV)
|
3
|
0.76(0.68~0.83)
|
0.56(0.48~0.63)
|
2.16(0.81~5.78)
|
0.41(0.24~0.70)
|
4.98(1.25~19.95)
|
0.81(0.77~0.85)
|
Sample type
|
Tissue
|
6
|
0.72(0.66~0.77)
|
0.71(0.66~0.76)
|
3.16(1.31~7.60)
|
0.37(0.25~0.53)
|
8.96(3.11~25.79)
|
0.83(0.78~0.88)
|
Plasma
|
1
|
/
|
/
|
/
|
/
|
/
|
/
|
miR-525 type
|
miR-525-5p
|
5
|
0.81(0.75~0.86)
|
0.83(0.78~0.87)
|
5.01(2.73~9.18)
|
0.25(0.15~0.43)
|
23.51(8.22~67.20)
|
0.90(0.83~0.97)
|
miR-525-3p
|
2
|
0.67(0.59~0.74)
|
0.29(0.19~0.41)
|
1.53(0.45~5.19)
|
0.59(0.29~1.20)
|
2.38(0.50~11.31)
|
/
|
Abbreviation: SEN, sensitivity; SPE, specificity; PLR, positive likelihood ratio; NLR, negative likelihood ratio; DOR, diagnostic odds ratio; AUC, area under curve.
And miR-525 was found to have high to moderate diagnostic accuracy in cancer of the female reproductive system (SEN = 0.89(0.80-0.94), SPE = 0.90(0.84-0.94)), Lymphoma (SEN = 0.77(0.69-0.85), SPE = 0.50(0.41-0.60), AUC = 0.84(0.80-0.88), and Gastrointestinal cancers (SEN = 0.65(0.77-0.73), SPE = 0.71(0.61-0.80)). Subgroup analysis of specimen type showed that miR-525 had high diagnostic accuracy for histological specimens (SEN = 0.72(0.66-0.77), SPE = 0.71(0.66-0.76), AUC = 0.83(0.78-0.88)), but among the included studies, there was only one study in which miR-525 was extracted from plasma for diagnostic analysis, which could not fully explain its diagnostic ability in different specimen types.
We conducted the sensitivity analysis by ignoring each of the included studies, and heterogeneity was found to be due to the perfect sensitivity (SEN = 1), high specificity (SPE = 0.9), high diagnostic odds ratio (DOR = 801.29), high positive likelihood ratio (PLR = 11) and very low negative likelihood ratio (NLR = 0.01) of one included individual study (Ilona Hromadnikova et al, 2017), with a significant decrease in heterogeneity after removing this study (data not shown)[23].
Results of prognostic meta-analysis:
We extracted relevant OS and RFS data from the 3 included studies, and miR-525 was low expressed in cancer specimen of all the included studies[26–28]. The prognostic meta-analysis was conducted by random-effects model, with the pooled HR, 95%CI = 0.17(0.07-0.41), and this result indicated that the low expression of miR-525 may be a protective factor for the prognosis of cancer patients, that is, cancer patients with high expression of miR-525 might have a poor prognosis (Figure4). The total I2 of the included studies was 0, with no significant heterogeneity. However, subgroup analysis results showed that there were no statistically significant differences (p-value > 0.05) among subgroups of cancers in different ethnic groups (Asian or Caucasian), year of publication (before 2020 or after 2020), different detection methods (TaqMan or SYBR), different TNM stages and different types of cancer (digestive system tumors, female reproductive system tumors, lymphoma, and female reproductive system tumors) (Table5 and FigureS4 in Additional File 2). Sensitivity analysis indicated that there was no significant heterogeneity among the included studies (Figure5).
Table 5: Subgroup analysis of the prognosis value of the miR-525 in various cancers.
Sub-group
|
|
N of studies
|
HR (95% CI)
Fixed
|
Heterogeneity between groups
|
Heterogeneity
|
P groups
|
I2
|
I2
|
PH
|
Publication year
|
≤2020
|
1
|
0.20(0.05~0.75)
|
0.687
|
0
|
0
|
0
|
>2020
|
2
|
0.14(0.04~0.49)
|
0
|
0.515
|
Cancer types
|
Lymphoma
|
1
|
0.14(0.04~0.49)
|
0.746
|
0
|
0
|
0
|
Female Reproductive System Tumor
|
1
|
0.13(0.02~0.84)
|
0
|
0
|
Neuroendocrine System Tumors
|
1
|
0.31(0.05~1.92)
|
0
|
0
|
TNM stage
|
(I-II)
|
1
|
0.13(0.02~0.84)
|
0.763
|
0
|
0
|
0
|
(III-IV)
|
2
|
0.18(0.06~0.51)
|
0
|
0.481
|
Assay type
|
TaqMan
|
1
|
0.13(0.02~0.84)
|
0.763
|
0
|
0
|
0
|
SYBR
|
2
|
0.18(0.06~0.51)
|
0
|
0.481
|
Abbreviation: HR, hazard ratio.
Publication bias:
Deeks' funnel plot showed that no publication bias was found among the 7 studies included in the diagnostic meta-analysis (p-value = 0.903, Figure6A)[21–27]. We conducted Begg’s test and Egger’s test and used the Funnel Plot for evaluating publication bias of the included 3 studies through the random-effects model, and the result shown in the Funnel Plot (included studies were evenly distributed on both sides of the central axis of the funnel plot), Begg’s test (p-value = 1.00) and Egger’s test (p-value = 0.683) had suggested that publication bias was not found in the 3 studies included for prognosis meta-analysis (Figure6B-D) [26–28].