Study identification and characteristics
As shown by the search flow diagram (Fig 1),a total11 studies[7-12, 15-19] with 1210 patients were enrolled in this meta-analysis according to the inclusion criteria, including 3studies on CRC, 3studies on HCC, 2 studies on GC, 1 study on RCC, 1 study on OSC, and 1 study on glioma. The included studies were published from 2015 to 2020, and sample sizes ranged from 30 to 187 patients. All of included studies were from China. Nine studies were published in English and two in Chinese. All of included studies received scores ≥6 in methodological assessments, which meant they had high quality. The clinicopathological characteristics and survival information obtained from these studies are summarized in Table1and Table2.
FTX expressionand clinicopathological characteristics
The pooled ORs with 95% CI are shown in Table 3. The results revealed that elevated FTX expression was significantly related to lymph node metastasis (yes vs no: OR = 2.47, 95% CI = [1.45, 4.22], p = 0.001, Fig. 2b) in 7 studies[7, 9, 10, 12, 16-18] (3 studies on CRC，2 studies on GC，1 study on HCC, and 1 study on RCC),distant metastasis (yes vs no: OR = 3.87, 95% CI = [2.38, 6.30], p < 0.001, Fig. 2c) in 5 studies[7, 8, 12, 17, 18] (2 studies on CRC，1 study on GC，1 study on HCC, and 1 study on OSC),bigger tumor size (the bigger group vs the small group: OR = 2.10, 95% CI = [1.15, 3.85], p = 0.016, Fig. 2d) in 9 studies[7-12, 17-19] (2 studies on CRC，2 studies on GC，3 studies on HCC, 1 study on RCC, and 1 study on OSC),and later TNM/clinical stage (III + IV vs I + II : OR = 2.38, 95% CI = [1.85, 3.06], p < 0.001, Fig. 2f) in 10 studies[7-11, 15-19] (3 studies on CRC，2 studies on GC，2 studies on HCC, 1 study on RCC, 1 study on OSC, and 1 study on glioma).The overexpression of FTX was not associated with gender (male vs female: OR = 0.87, 95% CI = [0.68, 1.12], p = 0.271, Fig. 2a) in all aforementioned 11 studies and differentiation (low vs high and moderate: OR = 1.33, 95% CI = [0.53, 3.33], p = 0.546, Fig. 2e) in 7 studies[9, 11, 12, 16-19] (2 studies on CRC，3 studies on GC，and 2 studies on HCC).The findings suggest that high expression of FTX is associated with some clinicopathological parameters of the aforementioned cancers.
FTX expression and survival outcomes
A meta-analysis was conducted using the data from survival analysis by Kaplan-Meier method in 8 studies[8, 9, 11, 12, 15, 16, 18, 19] (3 studies on HCC,2 studies on CRC,1study on GC,1 study on OSC, and 1study on glioma). The pooled HRs for OS was extracted from these 8 heterogeneous studies(I2 = 68.3%, p = 0.002) with 937 patients, and the result showed a significant correlation between high FTX expression and a shorter OS(high vs low: HR = 1.58, 95% CI = [1.13, 2.20], p ＝0.007, Fig. 3a). In addition, the 2 heterogeneous studies[12, 19] (I2 =86.8%, P =0:006)with 199 patients with HCC were included, and the pooled results indicated that high FTX expression was related to a shorter DFS(high vs low: HR = 3.78, 95% CI = [1.08, 13.22], p =0037, Fig. 3b).
Another meta-analysis was conducted using the data from survival analysis by multivariate Cox regression model in four studies[8, 12, 15, 16] (1 study on CRC, 1 study on HCC, 1 study on OSC,1 study on glioma), which included531 patients. The role of FTX as an independent predictive factor for OS of patients with cancer was assessed. The pooled results showed that high FTX expression was an independent prognostic factor for a shorter OS of patients with the aforementioned 4 cancers (HR = 2.63, 95% CI = [2.01, 3.45], p＜0.001, Fig. 3c).
We performed sensitivity analyses to evaluate the robustness of the prognostic value. The results (Supplementary table1 and Supplementary table2) were not significantly impacted when any individual study was removed, demonstrating that the results were reliable.
Begg's funnel analysis was conducted to evaluate publication bias. As shown in Fig. 4,there was no publication bias for gender (p = 0.276),lymph node metastasis(p=0.764),distant metastasis(p=1.0),tumor size(p=0.754),differentiation(p=1.0),TNM/clinical stage(p=0.858),OS(p=0.174)，DFS（p=1.0）and independent factor for OS (p = 0.308).