The role of RCAS1 as a biomarker in diagnosing CRC and monitoring tumor recurrence and metastasis

IBSP, a potential recurrence biomarker, promotes the progression of colorectal cancer via Fyn/β-catenin signaling pathway

Colorectal cancer (CRC) is a frequently occurring digestive system cancer and postoperative tumor metastasis and recurrence are the main reasons for the failure of CRC treatment. The aim of this study was to identifying and validating key genes associated with metastatic recurrence of CRC. RNA expression of three datasets (GSE17538, GSE32323, and GSE29623) was used for biomarker discovery. We identified integrin-binding sialoprotein (IBSP) as a candidate biomarker which was validated in three clinical cohorts (GSE41258, GSE21510, and GSE39582) and our clinical specimens. The results suggested that IBSP expression significantly increased at mRNA and protein levels among CRC cases, which was associated with metastatic recurrence, metastasis, high risk of recurrence, and poor survival in CRC. Consistent results were obtained in CRC cells. The relative level of serum IBSP evidently increased among CRC patients relative to normal controls, and downregulated after operation. As suggested by gene set enrichment analysis (GSEA), the IBSP level was associated with cell-matrix adhesion in CRC. Functional experiments in vitro showed that IBSP promoted the growth and aggressiveness of CRC, and the potential mechanism by which IBSP promoted carcinogenesis of CRC was the abnormal activation of Fyn/β-catenin signaling pathway. To sum up, findings in the present work indicate that IBSP can serve as the candidate biomarker for the diagnosis, treatment, and prognosis of CRC.

High post-treatment serum soluble receptor-binding cancer antigen expressed on SiSo cells (sRCAS1) levels is associated with poor survival of patients with cervical cancer

AIM

Receptor-binding cancer antigen expressed on SiSo cells (sRCAS1) is responsible for induction of selective immunosuppression. In addition, preclinical studies have shown that sRCAS1 levels may reflect cancer aggressiveness. The main aim of our study was to analyze pre- and post-treatment levels of sRCAS1 in the sera of patients treated for cervical cancer and to evaluate whether the levels change during treatment and their impact on patient prognosis.

METHODS

The study included 49 patients suffering from cervical cancer. The early stage cervical cancer patients (14) were treated surgically, while the advanced stage patients (35) underwent radiochemotherapy. Serum sRCAS1 levels were evaluated both before and after intervention with the use of the ELISA method.

RESULTS

We have found that median serum sRCAS1 levels of patients before intervention were not significantly different from the levels assessed after intervention. There were also no differences when pre- and post-treatment levels were compared within the group of early and of advanced stage patients. Serum sRCAS1 levels were not influenced by either the histopathological type of the tumor or the methods of treatment. High post-intervention sRCAS1 levels indicated shortened OS when compared to low sRCAS1 levels. Neither pre-intervention sRCAS1 levels nor the alteration in sRCAS1 levels during treatment were associated with patient prognosis. In multivariate analysis, post-treatment sRCAS1 levels and clinical stage of cervical cancer remained as independent predictors of survival.

CONCLUSION

High post-treatment serum sRCAS1 level in cervical cancer patients seems to be a negative prognostic factor for patient overall survival.

Quantitative detection of the tumor-associated antigen large external antigen in colorectal cancer tissues and cells using quantum dot probe

The large external antigen (LEA) is a cell surface glycoprotein that has been proven to be highly expressed in colorectal cancer (CRC) as a tumor-associated antigen. To evaluate and validate the relationship between LEA expression and clinical characteristics of CRC with high efficiency, LEA expression levels were detected in 85 tissue blocks from CRC patients by quantum dot-based immunohistochemistry (QD-IHC) combined with imaging quantitative analysis using quantum dots with a 605 nm emission wavelength (QD605) conjugated to an ND-1 monoclonal antibody against LEA as a probe. Conventional IHC was performed in parallel for comparison. Both QD-IHC and conventional IHC showed that LEA was specifically expressed in CRC, but not in non-CRC tissues, and high LEA expression was significantly associated with a more advanced T-stage (P<0.05), indicating that LEA is likely to serve as a CRC prognostic marker. Compared with conventional IHC, receiver operating characteristic analysis revealed that QD-IHC possessed higher sensitivity, resulting in an increased positive detection rate of CRC, from 70.1% to 89.6%. In addition, a simpler operation, objective analysis of results, and excellent repeatability make QD-IHC an attractive alternative to conventional IHC in clinical practice. Furthermore, to explore whether the QD probes can be utilized to quantitatively detect living cells or single cells, quantum dot-based immunocytochemistry (QD-ICC) combined with imaging quantitative analysis was developed to evaluate LEA expression in several CRC cell lines. It was demonstrated that QD-ICC could also predict the correlation between LEA expression and the T-stage characteristics of the cell lines, which was confirmed by flow cytometry. The results of this study indicate that QD-ICC has the potential to noninvasively detect rare circulating tumor cells in clinical samples in real clinical applications.