Previstage™ GCC Colorectal Cancer Staging Test: A New Molecular Test to Identify Lymph Node Metastases and Provide More Accurate Information about the Stage of Patients with Colorectal Cancer

Colorectal Carcinoma: A General Overview and Future Perspectives in Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer-related death. Most cases of CRC are detected in Western countries, with its incidence increasing year by year. The probability of suffering from colorectal cancer is about 4%–5% and the risk for developing CRC is associated with personal features or habits such as age, chronic disease history and lifestyle. In this context, the gut microbiota has a relevant role, and dysbiosis situations can induce colonic carcinogenesis through a chronic inflammation mechanism. Some of the bacteria responsible for this multiphase process include Fusobacterium spp, Bacteroides fragilis and enteropathogenic Escherichia coli. CRC is caused by mutations that target oncogenes, tumour suppressor genes and genes related to DNA repair mechanisms. Depending on the origin of the mutation, colorectal carcinomas can be classified as sporadic (70%); inherited (5%) and familial (25%). The pathogenic mechanisms leading to this situation can be included in three types, namely chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylator phenotype (CIMP). Within these types of CRC, common mutations, chromosomal changes and translocations have been reported to affect important pathways (WNT, MAPK/PI3K, TGF-β, TP53), and mutations; in particular, genes such as c-MYC, KRAS, BRAF, PIK3CA, PTEN, SMAD2 and SMAD4 can be used as predictive markers for patient outcome. In addition to gene mutations, alterations in ncRNAs, such as lncRNA or miRNA, can also contribute to different steps of the carcinogenesis process and have a predictive value when used as biomarkers. In consequence, different panels of genes and mRNA are being developed to improve prognosis and treatment selection. The choice of first-line treatment in CRC follows a multimodal approach based on tumour-related characteristics and usually comprises surgical resection followed by chemotherapy combined with monoclonal antibodies or proteins against vascular endothelial growth factor (VEGF) and epidermal growth receptor (EGFR). Besides traditional chemotherapy, alternative therapies (such as agarose tumour macrobeads, anti-inflammatory drugs, probiotics, and gold-based drugs) are currently being studied to increase treatment effectiveness and reduce side effects.

Combined preoperative CEA and CD44v6 improves prognostic value in patients with stage I and stage II colorectal cancer

AIM

Combination of biomarkers may improve diagnosis and have better prognostic value than single markers. The purpose of this study was to investigate whether combined CEA and CD44v6 improves prognostic value in stage I and stage II (stage I/II) colorectal cancer (CRC).

METHODS

Preoperative serum CEA level and the expression of CD44v6 in CRC tissues were examined by electrochemiluminescence immunoassay and immunohistochemistry, respectively. The association of CEA and CD44v6 with clinicopathological features and their possible prognostic values was analyzed.

RESULTS

The preoperative elevated serum CEA level and positive CD44v6 expression were detected in 30.1 % (52/173) serum samples and 60.5 % (101/167) CRC tissues, respectively. Patients with an elevated-CEA level or a CD44v6-negative tumor had a worse disease-specific survival (DSS) than those with a normal-CEA level or CD44v6-positive tumor (P = 0.024, P = 0.012, respectively). Moreover, CD44v6 expression could be used in discriminating patients from good to poor prognosis in normal-CEA subgroup (P = 0.043), but not in elevated-CEA subgroup (P = 0.563). Multivariate analysis revealed that combined CEA and CD44v6 was an independent prognostic factor for patients with stage I/II CRC (P = 0.023). However, serum CEA level only retained a borderline significance for correlation with a worse DSS (P = 0.059), and CD44v6 expression alone was not an independent prognostic factor for DSS in multivariate analysis (P = 0.123).

CONCLUSION

These results suggested that combined CEA/CD44v6 had better prognostic value than CEA or CD44v6 alone for patients with stage I/II CRC.

Correlations between cytoplasmic CSE1L in neoplastic colorectal glands and depth of tumor penetration and cancer stage

Background

Colorectal carcinomas spread easily to nearby tissues around the colon or rectum, and display strong potential for invasion and metastasis. CSE1L, the chromosome segregation 1-like protein, is implicated in cancer progression and is located in both the cytoplasm and nuclei of tumor cells. We investigated the prognostic significance of cytoplasmic vs. nuclear CSE1L expression in colorectal cancer.

Methods

The invasion- and metastasis-stimulating activities of CSE1L were studied by in vitro invasion and animal experiments. CSE1L expression in colorectal cancer was assayed by immunohistochemistry, with tissue microarray consisting of 128 surgically resected specimens; and scored using a semiquantitative method. The correlations between CSE1L expression and clinicopathological parameters were analyzed.

Results

CSE1L overexpression was associated with increased invasiveness and metastasis of cancer cells. Non-neoplastic colorectal glands showed minimal CSE1L staining, whereas most colorectal carcinomas (99.2%, 127/128) were significantly positive for CSE1L staining. Cytoplasmic CSE1L was associated with cancer stage (P=0.003) and depth of tumor penetration (P=0.007). Cytoplasmic CSE1L expression also correlated with lymph node metastasis of the disease in Cox regression analysis

Conclusions

CSE1L regulates the invasiveness and metastasis of cancer cells, and immunohistochemical analysis of cytoplasmic CSE1L in colorectal tumors may provide a useful aid to prognosis.

High nuclear expression of phosphorylated extracellular signal-regulated kinase in tumor cells in colorectal glands is associated with poor outcome in colorectal cancer

Extracellular signal-regulated kinase (ERK) is a major downstream transducer of Ras and plays an important role in transducing extracellular signals to the nuclei of cells. It is located in both the cytoplasm and the nucleus of cells. The nuclear localization of phosphorylated or activated ERK is involved in the invasive behavior of tumor cells. We studied the association between Ras mutation/ERK activation and the prognosis of patients with colorectal cancer. We analyzed 126 surgically resected colorectal cancer specimens for K-Ras mutation using direct sequencing. Activation/phosphorylation of ERK was assayed by immunohistochemistry with tissue microarray, and the staining intensity was analyzed using a semiquantitative scoring system. K-Ras mutations were detected in 32.5% (41/126) of the colorectal tumors. Colorectal glands are important functional organs in colorectal tissue and form the origin of colorectal carcinomas. Tissue microarray immunohistochemistry tests showed that tumors in colorectal cancer specimens were significantly stained for phospho-ERK (100%; 126/126), whereas nonneoplastic colorectal glands mainly showed faint phosphorylated ERK staining. High nuclear phospho-ERK expression in tumors was associated with highly invasive cancer stage and T status of the disease. Kaplan-Meier analysis showed that nuclear but not cytoplasmic phosphorylated ERK expression correlated with the patients' overall survival rate (P = .039). Colorectal adenomas including tubular adenomas and tubulovillous adenomas mainly showed weak cytoplasmic phospho-ERK expression. Our results suggest that immunohistologic analysis of phosphorylated ERK expression in colorectal glands may aid the diagnosis of colorectal cancer and that nuclear phosphorylated ERK might be a valuable prognostic marker for colorectal cancer.

Genetic and epigenetic traits as biomarkers in colorectal cancer

Colorectal cancer is a major health burden, and a leading cause of cancer-related deaths in industrialized countries. The steady improvements in surgery and chemotherapy have improved survival, but the ability to identify high- and low-risk patients is still somewhat poor. Molecular biology has, over the years, given insight into basic principles of colorectal cancer initiation and development. These findings include aberrations increasing risk of tumor development, genetic changes associated with the stepwise progression of the disease, and errors predicting response to a specific treatment. Potential biomarkers in colorectal cancer are extensively studied, and how the molecular aberrations relate to clinical features. Yet, little of this knowledge has been possible to transfer into clinical practice. In this review, an overview of colorectal cancer genetics will be given, as well as how aberrations found in this tumor type are proposed as biomarkers for risk prediction, as diagnostic tools, for prognosis or prediction of treatment outcome.

Epitope-targeted cytotoxic T cells mediate lineage-specific antitumor efficacy induced by the cancer mucosa antigen GUCY2C

Guanylyl cyclase C (GUCY2C) is the index cancer mucosa antigen, an emerging class of immunotherapeutic targets for the prevention of recurrent metastases originating in visceral epithelia. GUCY2C is an autoantigen principally expressed by intestinal epithelium, and universally by primary and metastatic colorectal tumors. Immunization with adenovirus expressing the structurally unique GUCY2C extracellular domain (GUCY2C(ECD); Ad5-GUCY2C) produces prophylactic and therapeutic protection against GUCY2C-expressing colon cancer metastases in mice, without collateral autoimmunity. GUCY2C antitumor efficacy is mediated by a unique immunological mechanism involving lineage-specific induction of antigen-targeted CD8(+) T cells, without CD4(+) T cells or B cells. Here, the unusual lineage specificity of this response was explored by integrating high-throughput peptide screening and bioinformatics, revealing the role for GUCY2C-directed CD8(+) T cells targeting specific epitopes in antitumor efficacy. In BALB/c mice vaccinated with Ad5-GUCY2C, CD8(+) T cells recognize the dominant GUCY2C(254-262) epitope in the context of H-2K(d), driving critical effector functions including interferon gamma secretion, cytolysis ex vivo and in vivo, and antitumor efficacy. The ability of GUCY2C to induce lineage-specific responses targeted to cytotoxic CD8(+) T cells recognizing a single epitope mediating antitumor efficacy without autoimmunity highlights the immediate translational potential of cancer mucosa antigen-based vaccines for preventing metastases of mucosa-derived cancers.

Radiometallated peptides targeting guanylate cyclase C and the urokinase-type plasminogen activator receptor

Research is currently underway worldwide into the development of receptor-specific radiopharmaceuticals for the imaging and treatment of cancer. The successful clinical development of radiolabeled somatostatin analogs for imaging and treatment of cancers overexpressing somatostatin receptors has catalyzed further preclinical investigation of other radiolabeled peptides for molecular imaging and peptide-receptor radiotherapy, including such well-studied peptide vectors as cholecystokinin, neurotensin, bombesin and RGD peptides. Within this larger context, this article will focus on the current status of two more recent additions to the list of molecular imaging targets – guanylate cyclase C, a specific marker for colorectal cancer, and the urokinase plasminogen activator receptor, a cell-surface receptor overexpressed in diverse cancer types.

Serum cellular apoptosis susceptibility protein is a potential prognostic marker for metastatic colorectal cancer

Colorectal cancer has high rates of recurrence and metastasis. Many patients with similar histopathological features show significantly different clinical outcomes, and these differences are primarily related to metastases undetected by current diagnostic methods. There is no useful serological marker for metastatic disease. We investigated the cellular apoptosis susceptibility (CSE1L/CAS) protein in comparison with carcinoembryonic antigen (CEA) as a marker for metastatic colorectal cancer. Using serum from 103 patients with stage I, II, III, and IV disease, CSE1L was detected in 36.0% (9 of 25), 57.7% (15 of 26), 71.4% (30 of 42), and 88.9% (8 of 9) of patients, respectively; a pathological CEA level was found in 16.0% (4 of 25), 42.3% (11 of 26), 47.6% (20 of 42), and 77.8% (7 of 9) of patients, respectively; a combined CSE1L/CEA assay was detected in 48.0% (12 of 25), 65.4% (17 of 26), 88.1% (37 of 42), and 100% (9 of 9) of patients, respectively. Lymphatic metastasis is an important predictor of poor prognosis and crucial for determination of therapeutic strategy. Serum CSE1L was detected in 74.5% (38 of 51) of patients with lymph node metastasis, whereas a pathological CEA level was found in only 52.9% (27 of 51) of the same patients (P < 0.001); the combined CSE1L/CEA assay increased sensitivity to 90.2% (46 of 51). Animal experiments showed CSE1L reduction in B16-F10 melanoma cells correlated with decreased metastasis to the colorectal tract in C57BL/6 mice. These results indicate that assay of serum CSE1L may facilitate diagnosis of colorectal cancer lymphatic metastases; furthermore, CSE1L is a possible therapeutic target.

Clinical biomarkers in oncology: focus on colorectal cancer

Rapidly growing insight into the molecular biology of colorectal cancer has led to high hopes for the identification of molecular markers to be used in optimized and tailored treatment regimens. However, many of the published data on gene-specific biomarkers are contradictory in their findings, and no tests are currently used in clinical practice, with the exception of microsatellite instability (MSI) and guanylyl cyclase C (GCC) testing in the adjuvant setting, and in Europe KRAS mutation testing is used in the setting of epidermal growth factor receptor (EGFR)-targeted therapy for metastatic disease. There are many reasons for the failure of the initial marker hypothesis-driven approach. Although supported by a good biologic rationale, single markers such as tumor protein p53 (TP53) gene mutations, when applied to a complex tumor type containing many synchronous alterations, do not perform well in predicting outcome. Many markers also suffer from technical shortcomings, resulting from the lack of quantitative techniques to capture the impact of the molecular alteration. The impact of markers obtained from microarray expression profiling needs to be further investigated in studies based on much larger cohorts, and cross-validation studies will be essential. Recently, mutations in the KRAS gene were shown to be strong negative predictors of response to EGFR inhibitors in metastatic disease. It has also been suggested that BRAF gene mutations may be predictive of EGFR inhibitor resistance, and there are some conflicting data regarding the role of the PIK3CA gene. Further studies are needed to help integrate the latest findings into clinically useful tools for personalized medicine.