Detection of serum melanoma-associated antigen D4 in patients with squamous cell carcinoma of the esophagus

Identification of stromal cell-derived factor 4 as a liquid biopsy-based diagnostic marker in solid cancers

There is a need for serum diagnostic biomarkers to improve the prognosis of solid malignant tumors. Here, we conducted a single-institutional study to evaluate the diagnostic performance of serum stromal cell-derived factor 4 (SDF4) levels in cancer patients. Serum samples were collected from a total of 582 patients with solid cancers including gastric cancer (GC) and 80 healthy volunteers. SDF4 protein levels in sera, and conditioned media or lysates of human GC cell lines were measured by enzyme-linked immunosorbent assay, and those in GC tissue by immunohistochemistry. Serum SDF4 levels were higher in patients with cancer than the healthy control in all cancer type. Regarding GC, serum SDF4 levels distinguished healthy controls from GC patients with the area under the curve value of 0.973, sensitivity of 89%, and specificity of 99%. Serum SDF4 levels were significantly elevated in patient with early stage GC. In immunohistochemistry, the frequency of SDF4-positive GC tumors did not vary significantly between GC stages. The ability of human GC cell lines to both produce and secrete SDF4 was confirmed in vitro. In conclusion, serum SDF4 levels could be a promising candidate for a novel diagnostic biomarker for GC and other malignancies.

G-protein subunit gamma-4 expression has potential for detection, prediction and therapeutic targeting in liver metastasis of gastric cancer

BACKGROUND

The liver is the most common site for haematogenous metastasis of gastric cancer, and liver metastasis is fatal.

METHODS

We conducted a transcriptomic analysis between metastatic foci in the liver, primary tumour and adjacent tissues from gastric cancer patients with metastasis limited to the liver. We determined mRNA expression levels in tumour tissues of 300 patients with gastric cancer via quantitative RT-PCR. The oncogenic phenotypes of GNG4 were determined with knockdown, knockout and forced expression experiments. We established and compared subcutaneous and liver metastatic mouse xenograft models of gastric cancer to reveal the roles of GNG4 in tumorigenesis in the liver.

RESULTS

GNG4 was upregulated substantially in primary gastric cancer tissues as well as liver metastatic lesions. High levels of GNG4 in primary cancer tissues were associated with short overall survival and the likelihood of liver recurrence. Functional assays revealed that GNG4 promoted cancer cell proliferation, the cell cycle and adhesiveness. Tumour formation by GNG4-knockout cells was moderately reduced in the subcutaneous mouse model and strikingly attenuated in the liver metastasis mouse model.

CONCLUSIONS

GNG4 expression may provide better disease monitoring for liver metastasis, and GNG4 may be a novel candidate therapeutic target for liver metastasis.