Expression and prognostic value of MG7-Ag in patients with surgically resectable esophageal squamous cell carcinoma

Elevated expression of MGb2-Ag/TRAK1 is correlated with poor prognosis in patients with colorectal cancer

PURPOSE

MGb2, a mouse-derived monoclonal antibody specific to gastric carcinoma, was developed in our laboratory. Nevertheless, the potential role of MGb2-antigen/TRAK1 (MGb2-Ag/TRAK1) in colorectal cancer (CRC) is unclear. The aim of this study was to investigate the relationship between MGb2-Ag/TRAK1 expression and the clinicopathological characteristics of CRC. The potential utility of MGb2-Ag/TRAK1 expression as a prognostic indicator was also evaluated.

METHODS

Immunohistochemistry and western blot were used to detect MGb2-Ag/TRAK1 expression in 140 CRC tissues. The relationship between MGb2-Ag/TRAK1 expression and clinicopathological characteristics and postoperative survival time was statistically analyzed.

RESULTS

MGb2-Ag/TRAK1 expression in CRC tissues was significantly higher than in normal tissues and was positively correlated with tumor differentiation (p = 0.006), invasion (p = 0.049), and pathological stage (p = 0.032). There was no significant difference between MGb2-Ag/TRAK1 expression and the age or gender of the patient, lymphatic invasion, or distant metastasis (p = 0.586, 0.308, 0.910, and 0.068, respectively). The survival time of CRC patients with high expression of MGb2-Ag/TRAK1 was shorter than the survival time of patients with low MGb2-Ag/TRAK1 expression. Both univariate and multivariate analyses showed that tumor differentiation and MGb2-Ag/TRAK1 expression were two independent and prognostic factors for CRC (p < 0.001).

CONCLUSIONS

MGb2-Ag/TRAK1 may play an important role in the development of CRC and may be a valuable prognostic indicator of CRC.

The value of MG7-Ag and COX-2 for predicting malignancy in gastric precancerous lesions

Here we aimed to first investigate the clinical value of combined detection of MG7-Ag and COX-2 (cyclo-oxygenase 2) in prediction of advances in gastric precancerous lesions. Immunohistochemical analysis was used to examine the expression of MG7-Ag and COX-2 in 396 cases of patients with gastric precancerous lesions, including 66 cases of atrophic gastritis, 106 cases of intestinal metaplasia, 174 cases of low-moderate-grade dysplasia and 50 cases of high-grade dysplasia. The relation of MG7-Ag and COX-2 staining with various clinicopathological features was analysed by follow-up study. The positive rates of MG7-Ag and COX-2 were increased gradually from atrophic gastritis (21.2%, 28.8%), intestinal metaplasia (36.8%, 44.3%), low-moderate-grade dysplasia (51.4%, 58.6%) to high-grade dysplasia (72%, 80%). Double positive staining of MG7-Ag and COX-2 in gastric precancerous lesions had an increased risk of precancerous progression over 22 times, compared with negative ones. However, the expression of MG7-Ag and COX-2 was not significantly correlated with age and gender of patients. MG7-Ag and COX-2 might play an important role in the process of carcinogenesis and progression of gastric cancer. Combined detection of MG7-Ag and COX-2 was of value of predicting early gastric cancer from precancerous lesions.

Detection of gastric carcinoma-associated antigen MG7-Ag in human sera using surface plasmon resonance sensor

BACKGROUND

MG7-Ag is a kind of gastric cancer-specific tumor-associated antigen and has been investigated to serve as a marker of gastric cancer for early diagnosis.

METHODS

Surface plasmon resonance (SPR) sensor was used for the detection of MG7-Ag in the sera of gastric cancer patients to develop an innovative, simple and rapid assay method for early diagnosis. The specific monoclonal MG7 antibodies were used as capture and detection receptors which were immobilized on the surface of SPR sensor chips for MG7-Ag identification in the human sera. The measurements include 9 cases of gastric cancer patients and 2 cases of healthy blood donors and a MKN45 cancer cell lysate solution sample for positive control.

RESULTS

The binding of MG7-Ag onto the sensor surface was observed from SPR spectra. The sera of most gastric cancer patients revealed much higher expression level of MG7-Ag than healthy human sera did in SPR measurement.

CONCLUSION

The initial results demonstrate that the SPR biosensor has the potential for its application in the early diagnosis of gastric cancer. However, more tests need to be done to confirm the detection limitation and the criterion for cancer risk evaluation in early diagnosis.

Identification of prognosis-related proteins in advanced gastric cancer by mass spectrometry-based comparative proteomics

PURPOSE

The objective of this study was to identify differentially expressed proteins of advanced gastric cancer from patients with different prognosis using NanoLC-MS/MS (LTQ) (nanoflow liquid chromatography system interfaced with a linear ion trap LTQ mass spectrometer).

METHODS

Eight gastric cancer patients with relatively early TNM stage and survival time >34 months were identified as good survival (group G), while the other eight with late stage and survival time <15 months as poor survival (group P). The total protein of the tissue samples from each group was extracted and pooled together respectively. The resulting two protein mixtures were trypsin-digested and analyzed using NanoLC-MS/MS (LTQ). Database searches were done against NCBI non-redundant database and SWISS-PROT database and the identified proteins were classified through an online Web Gene Ontology Annotation Plot tool. Immunohistochemistry was used to verify candidate prognosis-related proteins.

RESULTS

There were 284 and 213 proteins identified for group G and group P respectively. And 117 proteins were detected exclusively in group G and 46 proteins exclusively in group P. These protein markers function in calcium ion signaling pathway, cellular metabolism, cytoskeleton formation, stress reaction, etc. Among those, the down-regulated expression of S100P was verified to claim a poor clinical outcome of gastric cancer patients (P = 0.0375).

CONCLUSION

The MS-based proteomics approach is efficient in identifying differentially expressed proteins in relation to prognosis of advanced gastric cancer patients. These differentially expressed proteins could be potential prognosis-related cancer markers and deserve further validation and functional study.