Molecular aspects in the diagnosis of gastric cancer

Loss of large tumor suppressor 1 promotes growth and metastasis of gastric cancer cells through upregulation of the YAP signaling

Accumulating evidence shows that large tumor suppressor 1 (LATS1) as a novel resident governor of cellular homeostasis is implicated in multiple tumorigenic properties including cell growth, apoptosis and metastasis. However, the contribution of LATS1 to gastric carcinoma (GC) remains unclear. The correlation of LATS1 expression with clinicopathologic characteristics, GC prognosis and recurrence was analyzed by immunohistochemistry, Univariate and Kaplan-Meier analysis. Functional experiments were performed to investigate biological behaviors of GC cells and underlying molecular mechanisms. Tumor growth and metastasis was assessed in vivo using orthotopic implantation GC models in severe combined immune deficiency (SCID) mice. Consequently, decreased LATS1 expression was significantly associated with the lymph node metastasis, poor prognosis and recurrence. Ectopic expression of LATS1 decreased GC cell proliferation and invasion in vitro and inhibited tumor growth and liver metastasis in vivo, but depletion of LATS1 expression restored the invasive phenotype. Further observation indicated that YAP pathway was required for LATS1-induced inhibition of cell growth and invasion, and LATS1 restrained nuclear transfer of YAP, downregulated YAP, PCNA, CTGF, MMP-2, MMP-9, Bcl-2 and CyclinD1 expression and upregulated p-YAP and Bax expression. Our findings suggest that LATS1 is a potential candidate tumor suppressor and inhibits the growth and metastasis of GC cells via downregulation of the YAP signaling.

Polymorphisms in CARS are associated with gastric cancer risk: a two-stage case-control study in the Chinese population

BACKGROUND

The cysteinyl transfer RNA synthetase gene (CARS) is located on chromosome band 11p15.5, which is an important tumor-suppressor gene region. Mutations in CARS have been identified in many kinds of cancers; however, evidence for a relationship between genetic variants in CARS and gastric cancer at the population level is still lacking. Thus, we explored the association of variants in CARS with gastric cancer using a two-stage case-control strategy in Chinese.

METHODS

We undertook a two-stage case-control study to investigate the association between polymorphisms in CARS and risk of gastric cancer with use of an Illumina Infinium^® BeadChip and an ABI 7900 system.

RESULTS

Four single nucleotide polymorphisms (SNPs) were significantly associated with gastric cancer risk in both the discovery stage and the validation stage after adjustment for age and sex. In addition, the combined results of the two stages showed these SNPs were related to gastric cancer risk (P _{false discovery rate} ≤ 0.001 for rs384,490, rs729662, rs2071101, and rs7394702). In silico analyses revealed that rs384490 and rs7394702 could affect transcription factor response elements or DNA methylation of CARS, and rs729662 was associated with the prognosis of gastric cancer. Additionally, expression quantitative trait loci analysis showed rs384490 and rs729662 might alter expression of CARS-related genes.

CONCLUSIONS

The potential functional SNPs in CARS might influence the biological functions of CARS or CARS-related genes and ultimately modify the occurrence and development of gastric cancer in Chinese. Further large-scale population-based studies or biological functional assays are warranted to validate our findings.

Abnormal FHIT protein expression may be correlated with poor prognosis in gastric cancer: a meta-analysis

Our current meta-analysis is aimed to investigate the relationships between fragile histidine triad (FHIT) protein expression and prognosis in gastric cancer patients. We searched MEDLINE (1966 ~ 2013), the Cochrane Library Database (Issue 12, 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), Web of Science (1945 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013) without any language restrictions. The meta-analysis was conducted using the STATA 12.0 software. Crude hazard ratios (HR) with its 95 % confidence interval (95 % CI) were calculated. Eight clinical cohort studies with a total of 1,361 gastric cancer patients were involved in our meta-analysis. Our results revealed that FHIT-negative patients exhibited a shorter overall survival (OS) time than FHIT-positive patients (HR = 1.23, 95 % CI = 1.01 ~ 1.44, P < 0.001). Ethnicity-stratified analysis demonstrated that FHIT-negative patients have significantly poorer prognosis than FHIT-positive patients among both Caucasians and Asians (all P < 0.05). In conclusion, our meta-analysis provides evidences that negative expression of FHIT protein may be correlated with poor prognosis in patients with gastric cancer. Thus, FHIT expression level may be utilized as an independent prognostic marker for gastric cancer.