Prognostic value of carcinoembryonic antigen distribution in tumor tissue of colorectal carcinoma

Clinical implication of tissue carcinoembryonic antigen expression in association with serum carcinoembryonic antigen in colorectal cancer

This study aimed to evaluate the prognostic significance of carcinoembryonic antigen (CEA) expression in tumor tissues of patients with colorectal cancer (CRC). The cohort included 7,412 patients with CRC from January 2010 to December 2015. Survival outcomes were assessed based on tissue CEA (t-CEA) patterns and intensities. Three-year (76.7% versus 81.3%) and 5-year (71.7% versus 77.6%, p < 0.001) disease-free survival (DFS) rates were significantly (p < 0.001) poorer in patients with a diffuse-cytoplasmic pattern than an apicoluminal pattern. Three-year (79% versus 86.6%) and 5-year (74.6% versus 84.7%) DFS rates were also significantly (p < 0.001) poorer in patients with high than low t-CEA intensity. Three-year (84.6% versus 88.4%) and 5-year (77.3% versus 82.6%) overall survival (OS) rates were significantly (p < 0.001) poorer in patients with diffuse-cytoplasmic than apicoluminal pattern of CEA expression, and both 3-year (86.7% versus 91.2%) and 5-year (80.1% versus 87.7%) OS rates were significantly (p < 0.001) poorer in patients with high than low t-CEA intensity. Multivariate analyses showed that high-intensity t-CEA was independently associated with DFS (p = 0.02; hazard ratio [HR] = 1.233) and OS (p = 0.032; HR = 1.228). Therefore, high-intensity t-CEA is a significant prognostic factor in CRC, independent of serum CEA (s-CEA), and can complement s-CEA in predicting survival outcomes after CRC resection.

Fluorescence Molecular Targeting of Colon Cancer to Visualize the Invisible

Colorectal cancer (CRC) is a common cause of cancer and cancer-related death. Surgery is the only curative modality. Fluorescence-enhanced visualization of CRC with targeted fluorescent probes that can delineate boundaries and target tumor-specific biomarkers can increase rates of curative resection. Approaches to enhancing visualization of the tumor-to-normal tissue interface are active areas of investigation. Nonspecific dyes are the most-used approach, but tumor-specific targeting agents are progressing in clinical trials. The present narrative review describes the principles of fluorescence targeting of CRC for diagnosis and fluorescence-guided surgery with molecular biomarkers for preclinical or clinical evaluation.

THE Role of Preoperative carcinoembryonic antigen in recurrence of resectable colorectal carcinoma

In colorectal carcinoma, carcinoembryonic antigen (CEA) is a recommended marker for surveillance after curative resection. The aim of the present study was to determine the association of preoperative CEA with recurrence of colorectal carcinoma in our population. The study included 55 patients with all operable stages of colorectal adenocarcinoma treated during the 2012-2014 period, evaluated retrospectively and followed-up for recurrence for 2 years. Data on the baseline (preoperative) CEA levels were retrieved from patient files. On data analysis, SPSS 16.0 was used. In patients with normal preoperative CEA, the rate of recurrence was significantly low (p=0.008) and the likelihood of no recurrence 1.55-fold greater as compared to patients with raised initial CEA levels (p=0.028). In patients with raised preoperative CEA, the risk of recurrence was 5.26-fold greater as compared to those with normal CEA levels (p=0.028). A significant weak positive correlation (r_s=0.297) was found between raised CEA and recurrence. A highly significant (p=0.002) moderate positive correlation was recorded in patients aged <50 and moderate positive correlation of borderline significance in males (r_s=0.324, p=0.058). Sensitivity was 94.4% and specificity 32.4% in predicting recurrence. Accordingly, preoperative elevated CEA showed a significant weak positive correlation with recurrence while normal preoperative CEA moderately decreased the likelihood of recurrence.

Selection of optimal molecular targets for tumor-specific imaging in pancreatic ductal adenocarcinoma

Discrimination of pancreatic ductal adenocarcinoma (PDAC) from chronic pancreatitis (CP) or peritumoral inflammation is challenging, both at preoperative imaging and during surgery, but it is crucial for proper therapy selection. Tumor-specific molecular imaging aims to enhance this discrimination and to help select and stratify patients for resection. We evaluated various biomarkers for the specific identification of PDAC and associated lymph node metastases. Using immunohistochemistry (IHC), expression levels and patterns were investigated of integrin αvβ6, carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), Cathepsin E (Cath E), epidermal growth factor receptor (EGFR), hepatocyte growth factor receptor (c-MET), thymocyte differentiation antigen 1 (Thy1), and urokinase-type plasminogen activator receptor (uPAR). In a first cohort, multiple types of pancreatic tissue were evaluated (n=62); normal pancreatic tissue (n=8), CP (n=7), PDAC (n=9), tumor associated lymph nodes (n=32), and PDAC after neoadjuvant radiochemotherapy (n=6). In a second cohort, tissues were investigated (n=55) with IHC and immunofluorescence (IF) for concordance of biomarker expression in all tissue types, obtained from an individual patient. Integrin αvβ6 and CEACAM5 showed significantly higher expression levels in PDAC versus normal pancreatic tissue (P=0.001 and P<0.001, respectively) and CP (P=0.003 and P<0.001, respectively). Avβ6 and CEACAM5 expression identified tumor-positive lymph nodes correctly in 84% and 68%, respectively, and in 100% of tumor-negative nodes for both biomarkers. In conclusion, αvβ6 and CEACAM5 are excellent biomarkers to differentiate PDAC from surrounding tissue and to identify lymph node metastases. Individually or combined, these biomarkers are promising targets for tumor-specific molecular imaging of PDAC.

Correlation Between Preoperative Serum Carcinoembryonic Antigen Levels and Expression on Pancreatic and Rectal Cancer Tissue

Carcinoembryonic antigen (CEA)-targeted imaging and therapeutic agents are being tested in clinical trials. If CEA overexpression in malignant tissue corresponds with elevated serum CEA, serum CEA could assist in selecting patients who may benefit from CEA-targeted agents. This study aims to assess the relationship between serum CEA and CEA expression in pancreatic (n = 20) and rectal cancer tissues (n = 35) using histopathology. According to local laboratory standards, a serum CEA >3 ng/mL was considered elevated. In pancreatic cancer patients a significant correlation between serum CEA and percentage of CEA-expressing tumor cells was observed (P = .04, ρ = .47). All 6 patients with homogeneous CEA expression in the tumor had a serum CEA >3 ng/mL. Most rectal cancer tissues (32/35) showed homogeneous CEA expression, independent of serum CEA levels. This study suggests that selection of pancreatic cancer patients for CEA-targeted agents via serum CEA appears adequate. For selection of rectal cancer patients, serum CEA levels are not informative.

Relation between Carcinoembryonic Antigen Levels in Colon Cancer Tissue and Serum Carcinoembryonic Antigen Levels at Initial Surgery and Recurrence

OBJECTIVES

Carcinoembryonic antigen (CEA) is widely used for postoperative surveillance of colon cancer. Even if serum CEA is negative at initial surgery, it may turn positive at recurrence. We investigated the relation between serum CEA levels and the immunohistochemical staining status of CEA in the primary and resected metastatic tissues.

METHODS

Out of 224 patients with recurrent colon cancer between 1998 and 2012, we studied 46 patients in whom serum CEA levels were measured and immunohistochemical staining for CEA was possible in the primary and metastatic tissues.

RESULTS

The positive rate of serum CEA did not differ between initial surgery and recurrence, regardless of whether the cutoff value was set at 5 or 10 ng/ml (p = 0.829, p = 0.671). There was no relation between the CEA staining status and serum CEA level at initial surgery. However, the CEA staining status of metastatic tissue was significantly related to the serum CEA level at recurrence (p = 0.0046 and p = 0.0026).

CONCLUSIONS

The immunohistochemical staining status of CEA in metastatic tissue is closely related to the serum CEA level. This finding suggests that serum CEA levels are influenced not only by the CEA production capacity of cancer cells but also by the ability of the surrounding tissue to release CEA into the blood.

Prognostic Significance of Carcinoembryonic Antigen Staining in Cancer Tissues of Gastric Cancer Patients

PURPOSE

The aim of this study was to assess the significance of the correlation among tissue carcinoembryonic antigen (CEA) expression with serum CEA (sCEA) levels and long-term survival to highlight the clinical prognostic significance of tissue CEA expression in gastric cancer patients.

METHODS

Immunohistological method and radioimmunoassay were used to assess tissue and sCEA expression, respectively. Univariate and multivariate analyses were performed to determine correlations, and the Kaplan-Meier method was used to investigate the prognostic significance.

RESULTS

Our results demonstrate that tissue CEA in gastric cancer is significantly correlated with preoperative sCEA levels (p = 0.031), depth of invasion (p = 0.001), lymph node metastasis (p < 0.001), distant metastasis (p = 0.001), and TNM staging (p < 0.001). The 5-year survival rates were 67.6, 53.9, and 40.1 % for negatively, moderately, and intensely positively stained tissues (p < 0.001), and 57.0 and 37.9 % for serum with normal and elevated CEA expression (p = 0.031). Multivariate analysis revealed that tissue CEA can be considered an independent prognostic factor. Further analysis illustrated that patients with negative expression in both tissue and serum had better prognosis compared with those positively expressing CEA in both tissue and serum and/or those positively expressing CEA in either tissue or serum (p < 0.001). Our results also demonstrated that patients with negative tissue CEA staining and elevated sCEA expression had a better 5-year survival.

CONCLUSION

Tissue CEA expression in gastric cancer is directly correlated with sCEA levels and long-term prognosis. Thus, tissue CEA expression can be considered as a useful biomarker to improve the interpretation of sCEA levels in predicting long-term survival.

Investigation of nonspecific cross-reacting antigen 2 as a prognostic biomarker in bone marrow plasma from colorectal cancer patients

Carcinoembryonic antigen (CEA) is still the only routinely used biomarker in colorectal cancer (CRC), but its utility is hampered by poor specificity and sensitivity, and the search for novel biomarkers is highly warranted. The nonspecific cross-reacting antigen 2 (NCA-2), a truncated CEA species molecule which is transcribed from the same gene, has been suggested as an alternative biomarker to CEA. In the present work, specific immunofluorometric assays were used for detection of NCA-2 and full-length CEA in bone marrow plasma from 277 CRC patients to assess their value as prognostic biomarkers, and detection was also performed in tumor tissue and a CRC cell line. Elevated plasma CEA was associated with advanced tumor stage at diagnosis and adverse patient outcome, while for NCA-2, although the same trends were observed, no additional prognostic information was gained. While specific detection of NCA-2 was clearly achieved in plasma samples, cross-reactivity with full-length CEA was observed when the antigen was exposed to common fixation chemicals. The results from this study indicate that NCA-2 is probably not a prognostic biomarker in CRC and, furthermore, underline the issue of antibody specificity when investigating CEA species molecules.

Phylogenetic discordance of human and canine carcinoembryonic antigen (CEA, CEACAM) families, but striking identity of the CEA receptors will impact comparative oncology studies

Comparative oncology aims at speeding up developments for both, human and companion animal cancer patients. Following this line, carcinoembryonic antigen (CEA, CEACAM5) could be a therapeutic target not only for human but also for canine (Canis lupus familiaris; dog) patients. CEACAM5 interacts with CEA-receptor (CEAR) in the cytoplasm of human cancer cells. Our aim was, therefore, to phylogenetically verify the antigenic relationship of CEACAM molecules and CEAR in human and canine cancer.

Anti-human CEACAM5 antibody Col-1, previously being applied for cancer diagnosis in dogs, immunohistochemically reacted to 23 out of 30 canine mammary cancer samples. In immunoblot analyses Col-1 specifically detected human CEACAM5 at 180 kDa in human colon cancer cells HT29, and the canine antigen at 60, 120, or 180 kDa in CF33 and CF41 mammary carcinoma cells as well as in spontaneous mammary tumors. While according to phylogenicity canine CEACAM1 molecules should be most closely related to human CEACAM5, Col-1 did not react with canine CEACAM1, -23, -24, -25, -28 or -30 transfected to canine TLM-1 cells. By flow cytometry the Col-1 target molecule was localized intracellularly in canine CF33 and CF41 cells, in contrast to membranous and cytoplasmic expression of human CEACAM5 in HT29. Col-1 incubation had neither effect on canine nor human cancer cell proliferation. Yet, Col-1 treatment decreased AKT-phosphorylation in canine CF33 cells possibly suggestive of anti-apoptotic function, whereas Col-1 increased AKT-phosphorylation in human HT29 cells. We report further a 99% amino acid similarity of human and canine CEA receptor (CEAR) within the phylogenetic tree. CEAR could be detected in four canine cancer cell lines by immunoblot and intracellularly in 10 out of 10 mammary cancer specimens from dog by immunohistochemistry. Whether the specific canine Col-1 target molecule may as functional analogue to human CEACAM5 act as ligand to canine CEAR, remains to be defined. This study demonstrates the limitations of comparative oncology due to the complex functional evolution of the different CEACAM molecules in humans versus dogs. In contrast, CEAR may be a comprehensive interspecies target for novel cancer therapeutics.

Cell surface markers in colorectal cancer prognosis

The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC.