## 4 Discussion
concentration in serum was used to diagnose and treat ESCC patients early [56,57]. Likewise, MMP-9, MMP1, and MMP13 serum concentrations were linked to clinical stages, and tumor size may decrease the overall survival rate of the ESCC patients [58, 59, 60]. The upregulation of CXCL8 in the microenvironment may lead to ESCC tumor development. Its regulation is triggered by the activation of the Akt and Erk1/2 pathways. It was accelerating the cancer cell movement and penetration. It also affects the overall survival rate of the patients drastically [61, 62, 63, 64]. PLAU is abundantly elevated in ESCC, which triggers the formation of fibroblasts to inflammatory cancer-associated fibroblasts by activating the uPAR/Akt/NF-kB/IL8 pathway, which leads to a poor prognosis of ESCC patients [65]. The overexpression of MMP1 promoted tumor growth and metastasis by activating the PI3K/AKT pathway [50]. Furthermore, COL1A1 showed a poor survival rate associated with PI3K/Akt/mTOR, p53, apoptosis, and cell cycle pathway [66]. These findings imply that further research into the involvement of collagen family members in ESCC is needed in the future to advance ESCC identification and therapy [67]. Furthermore, the somatic mutations were identified and warranted meaningful association with decreased overall survival rate compared with wild-type. The mutated genes such as MMP9, PLAU, MMP13, and COL1A1 all drastically reduced the overall survival of ESCA patients. [PERSON] et al. also identified that the somatic mutations in NFE2L2, CDKN2A and, KMT2D in ESCC significantly diminish overall survivability compared with its wild-type [68]. Our results suggest, the mutations, on the other hand, are found in only a few samples. Even with its overexpression rather than the mutation, the overall survival rate is reduced significantly. The promoter methylation identified for the predicted HGsT10 genes based on the disease type by utilizing the TCGA ESCA samples consisted of 201 samples. The hypomethylulation was observed in MMP3, MMP1, CXCL8, SPP1, PLAU, MMP13, COL1A1, COL1A2, and PLAUR in ESCC patient's samples when compared with normal samples. Our promoter methylation results suggested that hypo-methylated nine genes among HGsT10 are overexpressed in ESCC patient samples. Our findings suggest that the hypo-methylation at the promoter region directly correlated with overexpression, which leads to tumor proliferation and poorer prognosis of ESCC patients, as noted in the overall survival analysis of HGsT10. [PERSON] et al. and [PERSON] et al. described that aberrant expression of overexpressed in the lung cancer 1 (OLC1) gene and the phospholipase C epsilon 1 (PLCE1) and nuclear factor-kappaB (NF-kappaB)-related proteins highly promote the ESCC tumorigenesis [69,70]. Likewise, [PERSON] et al. described that the downregulation of the ST6 GALNAC1 gene might be a possible causative gene for ESCC tumor proliferation due to its hypermethylation [71]. The MicroRNAs (miRNAs) regulate gene expressions in tumor and tumor-adjacent tissue [72]. [PERSON] et al. explained that miRNAs could facilitate communication between tumor cells and their surroundings and control tumor immunity by directly regulating genes associated with immune stimulation or inactivation [73]. Here, we analyzed prognostic miRNAs of crucial histopathological subtypes ESCC on the predicted HGsT10 genes from the GSE161533 dataset. The constructed miRNA-HGsT10 network consisted of 367 miRNAs. The top ten hub miRNAs (HmiRT10) were identified, which regulates HGsT10 (namely hsa-let-7b-5p, hsa-let-7f-5p, hsa-let-7c-5p, hsa-let-7d-5p, hsa-mir-19a-3p, hsa-mir-21-5p, hsa-let-7e-5p, hsa-let-7a-5p, hsa-mir-16-5p and hsa-mir-19b-3p). The miRNA hsa-let-7b-5p, hsa-let-7f-5p, hsa-let-7c-5p, hsa-let-7d-5p and hsa-let-7a-5p regulates the target genes COL1A1, COL1A2 and CXCL8. The miRNA hsa-let-7e-5p regulates CXCL8, COL1A2, and MMP9. Let-7 family miRNAs are known to serve as tumor suppressor genes, and decreased expression of these miRNAs is linked to a poor prognosis in cancer patients [74, 75, 76, 77].