Decreased expression of the ATM gene linked to poor prognosis for gastric cancer of different nationalities in Xinjiang

Prognostic biomarkers and molecular pathways mediating Helicobacter pylori–induced gastric cancer: a network-biology approach

Cancer of the stomach is the second most frequent cancer-related death worldwide. The survival rate of patients with gastric cancer (GC) remains fragile. There is a requirement to discover biomarkers for prognosis approaches. Helicobacter pylori in the stomach is closely associated with the progression of GC. We identified the genes associated with poor/favorable prognosis in H. pylori–induced GC. Multivariate statistical analysis was applied on the Gene Expression Omnibus (GEO) dataset GSE54397 to identify differentially expressed miRNAs (DEMs) in gastric tissues with H. pylori–induced cancer compared with the H. pylori–positive with non-cancerous tissue. A protein interaction map (PIM) was built and subjected to DEMs targets. The enriched pathways and biological processes within the PIM were identified based on substantial clusters. Thereafter, the most critical genes in the PIM were illustrated, and their prognostic impact in GC was investigated. Considering p-value less than 0.01 and |Log2 fold change| as >1, five microRNAs demonstrated significant changes among the two groups. Gene functional analysis revealed that the ubiquitination system, neddylation pathway, and ciliary process are primarily involved in H. pylori–induced GC. Survival analysis illustrated that the overexpression of DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, and TXNIP was associated with poor prognosis, while increased MRPS5 expression was related to a favorable prognosis in GC patients. DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, TXNIP, and MRPS5 may be considered prognostic biomarkers for H. pylori–induced GC. However, experimental validation is necessary in the future.

The ATM rs189037 G>A polymorphism is associated with the risk and prognosis of gastric cancer in Chinese individuals: A case-control study

The ataxia telangiectasia mutated (ATM) gene is involved in repairing DNA lesions and maintaining genome stability, which is related to cancer invasion and metastasis. This gene influences the risk of cancers. Many studies have demonstrated that the ATM rs189037 G>A polymorphism is linked with the risks of different types of cancer. However, no study has probed the relationship between the ATM rs189037 G>A polymorphism and gastric cancer (GC) risk. Therefore, the aims of this study were to investigate the association of the ATM rs189037 G>A polymorphism with the risk and prognosis of GC in a case-control investigation of 345 GC patients and 467 controls in China. The rs189037 G>A polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism. This polymorphism was related to a significantly higher risk of GC [AA vs. GG: OR (95% CI): 1.80 (1.20-2.70), P = 0.04; GG vs. AA + GA: 1.46 (1.08-1.98); A vs. G: 1.34 (1.10-1.64), P = 0.004]. Subgroup analyses showed significant associations with female gender, smoking, alcohol consumption, age ≥60 years, and positive Helicobacter pylori status. This polymorphism was also correlated with TNM stage III + IV and tumor size >4 cm. GC patients carrying the AA genotype of the rs189037 polymorphism also had lower overall survival. In conclusion, the ATM rs189037 G>A polymorphism was related to increased susceptibility to and poorer prognosis in GC in this Chinese population.

A 21‑gene Support Vector Machine classifier and a 10‑gene risk score system constructed for patients with gastric cancer

Gastric cancer (GC) ranks fifth in terms of incidence and third in terms of tumor mortality worldwide. The present study was designed to construct a Support Vector Machine (SVM) classifier and risk score system for GC. The GSE62254 (training set) and GSE26253 (validation set 2) datasets were downloaded from the Gene Expression Omnibus database. Furthermore, the gene expression profile of GC (validation set 1) was obtained from The Cancer Genome Atlas database. Differentially expressed genes (DEGs) between recurrent and non‑recurrent samples were determined using the limma package. The feature genes were selected using the Caret package, and an SVM classifier was built using the e1071 package. Using the penalized package, the optimal predictive genes for constructing a risk score system were screened. Finally, stratification analysis of clinical factors and pathway enrichment analysis were performed using Gene Set Enrichment Analysis. A total of 239 DEGs were identified in GSE62254, among which 114 DEGs were significantly associated with both recurrence‑free survival and overall survival. Subsequently, 21 feature genes were screened from the 114 DEGs, and an SVM classifier was built. A risk score system for survival prediction was constructed, following the selection of 10 optimal genes, including A‑kinase anchoring protein 12, angiopoietin‑like protein 1, cysteine‑rich sequence 1, myeloid/lymphoid or mixed‑lineage leukemia, translocated to chromosome 11, neuron navigator 3, neurobeachin, nephroblastoma overexpressed, pleiotrophin, tumor suppressor candidate 3 and zinc finger and SCAN domain containing 18. The stratification analysis revealed that pathological stage was an independent prognostic clinical factor in the high‑risk group. Additionally, eight significant pathways were associated with the 10‑gene signature. The SVM classifier and risk score system may be applied for classifying and predicting the prognosis of patients with GC, respectively.

Hsa_circ_0001546 acts as a miRNA-421 sponge to inhibit the chemoresistance of gastric cancer cells via ATM/Chk2/p53-dependent pathway

Circular RNAs (circRNAs) are a new class of noncoding RNAs, play a crucial role in tumor initiation and development. Hsa_circ_0001546 is a novel circular RNA that was downregulated in gastric cancer (GC) tissues, however its function and mechanism in GC has not been studied. Our study verified that circ_0001546 was decreased in GC and correlated with the poor prognosis. Next, Pull-down assay and dual-luciferase reporter assay verified that miR-421 was a target of circ_0001546 while ATM (Ataxia telangiectasia mutated) was target by miR-421. Overexpression of circ_0001546 inhibited the proliferation and chemoresistance of HGC-27 cells, and increased the expression of ATM. In addition, circ_0001546 overexpression reversed the effect of miR-421 overexpression. What is more, circ_0001546 inhibits the chemoresistance of HGC-27 cells to L-OPH (Oxaliplatin) may through the activation of the ATM/checkpoint kinase 2 (Chk2)/p53-dependent signaling pathway. In summary, our study proved that circ_0001546 sponges miR-421 to upregulate the expression level of ATM and inhibit the proliferation and chemoresistance through the activation of the ATM/Chk2/p53-dependent pathway.

Ataxia-Telangiectasia-Mutated Protein Expression as a Prognostic Marker in Adenoid Cystic Carcinoma of the Salivary Glands

PURPOSE

Adenoid cystic carcinoma (ACC) is a high-grade malignant tumor of the salivary glands, clinically characterized by multiple recurrences and late distant metastasis. Biological markers for assessing the prognosis of ACC have remained elusive. The purpose of this study was to investigate whether the protein expressions of ataxia telangiectasia mutated (ATM), p53, and ATM-mediated phosphorylated p53 are related to patient survival in ACC.

MATERIALS AND METHODS

In this study, 48 surgical samples were used to assess the expressions of ATM and its downstream target p53. Fisher's exact test and Kaplan-Meier analysis were conducted to evaluate the role of ATM, p53, and phospho-p53 (S15) protein expressions in predicting patient survival and distant metastasis.

RESULTS

Myb expression was positive in 85.4% of ACCs, but did not reflect patient survival rate. In contrast, low expression of ATM in cancer cells was significantly correlated with poor survival rate (p=0.037). Moreover, under positive p53 expression, low expression of ATM was highly predictive of poor survival in ACC (p=0.017).

CONCLUSION

These data indicate that combined assessment of ATM and p53 expression can serve as a useful prognostic marker for assessing survival rate in patients with ACC of the salivary glands.