Serological and immunohistochemical studies on sialylated carbohydrate antigens in colorectal carcinoma

Esophageal, gastric and colorectal cancers: Looking beyond classical serological biomarkers towards glycoproteomics-assisted precision oncology

Esophageal (OC), gastric (GC) and colorectal (CRC) cancers are amongst the digestive track tumors with higher incidence and mortality due to significant molecular heterogeneity. This constitutes a major challenge for patients' management at different levels, including non-invasive detection of the disease, prognostication, therapy selection, patient's follow-up and the introduction of improved and safer therapeutics. Nevertheless, important milestones have been accomplished pursuing the goal of molecular-based precision oncology. Over the past five years, high-throughput technologies have been used to interrogate tumors of distinct clinicopathological natures, generating large-scale biological datasets (e.g. genomics, transcriptomics, and proteomics). As a result, GC and CRC molecular subtypes have been established to assist patient stratification in the clinical settings. However, such molecular panels still require refinement and are yet to provide targetable biomarkers. In parallel, outstanding advances have been made regarding targeted therapeutics and immunotherapy, paving the way for improved patient care; nevertheless, important milestones towards treatment personalization and reduced off-target effects are also to be accomplished. Exploiting the cancer glycoproteome for unique molecular fingerprints generated by dramatic alterations in protein glycosylation may provide the necessary molecular rationale towards this end. Therefore, this review presents functional and clinical evidences supporting a reinvestigation of classical serological glycan biomarkers such as sialyl-Tn (STn) and sialyl-Lewis A (SLe^A) antigens from a tumor glycoproteomics perspective. We anticipate that these glycobiomarkers that have so far been employed in non-invasive cancer prognostication may hold unexplored value for patients' management in precision oncology settings.

High expression of sLex associated with poor survival in Argentinian colorectal cancer patients

AIM

Colorectal cancer (CRC) is one of the most prevalent malignancies in Argentina with 11,043 new cases and 6,596 deaths estimated to have occurred in 2008. The present study was developed to clarify the differential expression of MUC1, MUC2, sLex, and sLea in colorectal cancer patients and their relationship with survival and clinical and histological features.

METHODS

Ninety primary tumor samples and 43 metastatic lymph nodes from CRC patients were studied; follow-up was documented. Twenty-six adenoma and 68 histological normal mucosa specimens were analyzed. An immunohistochemical approach was applied and statistical analysis was performed.

RESULTS

In tumor samples, MUC1, sLea, and sLex were highly expressed (94%, 67%, and 91%, respectively); also, we found a significantly increased expression of the 3 antigens in primary tumors and metastatic lymph nodes compared with normal mucosa and adenomas. MUC2 was expressed in 52% of both normal mucosa and CRC samples; this reactivity significantly decreased in metastatic lymph nodes (p<0.05). A multiple comparison analysis showed that MUC1 and sLex discriminated among 3 groups: normal, adenoma, and CRC tissues. The increase of sLex expression showed an association with recurrence, and survival analysis showed that a high sLex staining was significantly associated with a poor survival. By multivariate analysis MUC1 inmunoreactivity correlated positively and significantly with tumor size, while MUC2 expression showed the opposite correlation.

CONCLUSIONS

The correlation of sLex overexpression in primary tumors and metastatic lymph nodes, the discrimination among the normal, adenoma, and CRC groups based on sLex expression, as well as its association with recurrence and survival, all suggest a prognostic role of sLex in Argentinian CRC patients.

Serum Sialyl Lewis x and cytokeratin 19 fragment as predictive factors for recurrence in patients with stage I non-small cell lung cancer

This study aimed to establish the clinical significance of preoperative serum cytokeratin 19 fragment (CYFRA21-1) and Sialyl Lewis(x) (SLX) in patients with stage I non-small cell lung cancer (NSCLC). The study involved 137 patients (87 male, 50 female; median age 69 years) with completely resected stage I NSCLC. SLX, carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), and CYFRA21-1 were examined. Receiver operator characteristic (ROC) curves were constructed to determine prognostic cut-off values. Among the 137 patients, we identified 30 with recurrence within 3 years. The 5-year survival rates in patients with (n=30) and without (n=107) recurrence were 14% and 81%, respectively. The serum concentrations of SLX, CEA, and CYFRA21-1 in the recurrence group were significantly higher than those in the non-recurrence group. The areas under the ROC curve (AUC) were 0.72, 0.65, 0.53, and 0.64 for SLX, CEA, SCC, and CYFRA21-1, respectively. The prognostic cut-off values were 36U/ml, 7.8ng/ml, 1.5ng/ml, and 3.2ng/ml for SLX, CEA, SCC, and CYFRA21-1, respectively. A log-rank test revealed that age, performance status, T factor, lymphatic invasion, vascular invasion, SLX, CEA, SCC, and CYFRA21-1 were all significantly associated with survival. By multivariate analysis, age, performance status, lymphatic invasion, SLX (risk ratio, 4.11) and CYFRA21-1 (risk ratio, 3.47) were independent prognostic factors. For patients positive for both CYFRA21-1 and SLX, the relative risk was 5.32 compared with patients who were negative for both markers. The 5-year survival rates were 80% in the group negative for both markers (n=86); 52% in the group positive for one of the markers (n=43); and 13% for the group positive for both markers (n=8) (p<0.001). We concluded that serum SLX and CYFRA21-1 were prognostic markers for stage I NSCLC. Their combination should contribute to the classification of stage I NSCLC patients. There is a need to consider adjuvant and neoadjuvant therapies to improve prognosis in patients positive for both tumor markers.

Clinical Value of Serum Cytokeratin 19 Fragment and Sialyl-Lewis X in Non-Small Cell Lung Cancer

BACKGROUND

This study aimed to establish the clinical significance of preoperative serum cytokeratin 19 fragment (CYFRA21-1) and sialyl-Lewis x (SLex) as prognostic markers.

METHODS

The study involved 272 patients (181 male, 91 female; median age 69 years; range, 32 to 92) with non-small cell lung cancer (NSCLC) who underwent pulmonary resection with mediastinal lymph node dissection. Tumor markers carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC), CYFRA21-1, and SLex were examined.

RESULTS

A log-rank test revealed that age, gender, performance status, CEA, SCC, CYFRA21-1, and SLex were associated with the survival rate. By multivariate analysis, age, gender, performance status, CYFRA21-1 (risk ratio, 2.42) and SLex (risk ratio, 6.18) were independent prognostic factors. For patients positive for both markers, the relative risk was 6.10 compared with patients negative for both markers. The patients were divided into three groups: negative for both CYFRA21-1 and SLex (n = 97); positive for either marker (n = 136); and positive for both markers (n = 39). The 1-, 3-, and 5-year survival rates were the following: 98%, 82%, and 75% in the first group; 90%, 63%, and 49% in the second group; and 62%, 31%, and 25% in the third group (p < 0.001). Sixty-four percent of patients positive for both markers were histologic stage III/IV, and 68% of patients negative for both markers were stage I.

CONCLUSIONS

Serum CYFRA21-1 and SLex were prognostic markers for NSCLC. Their combination should contribute to the classification of NSCLC patients. Preoperative staging should be carefully performed in patients positive for both tumor markers.

High serum concentrations of Sialyl Lewisx predict multilevel N2 disease in non-small-cell lung cancer

BACKGROUND

The purpose of this study was to analyze the clinical significance of serum Sialyl Lewisx (SLX) concentrations as a predictor of N2 disease in patients with non-small-cell lung cancer.

METHODS

The study included 272 patients with non-small-cell lung cancer who underwent pulmonary resection in our institution between January 1998 and December 2003. Of 272 patients, the serum concentrations of SLX were measured by using a commercially available radioimmunoassay kit.

RESULTS

The 5-year survival rates of patients with concentrations of SLX > 38 U/mL and those with lower concentrations were 32% and 69%, respectively (P < .0001). The median serum concentration of SLX in patients with multilevel N2 or N3, single-level N2, and N0/1 disease were 44, 30, and 27 U/mL, respectively. The concentrations of serum SLX in patients with multilevel N2 disease were significantly higher than those in patients with single-level N2 or those with N0/1 disease (Mann-Whitney U-test; P < .0001). Although the sensitivity of SLX for identifying patients with non-small-cell lung cancer was only 24% in all patients, the sensitivity of SLX increased as the N-factor increased; the sensitivity of N0/1 disease was 15%, that of single-level N2 disease was 22%, and that of multilevel N2 or N3 disease was 71%.

CONCLUSIONS

High serum concentrations of SLX predicted multilevel N2 disease and the associated poor outcome. Although the sensitivity of serum SLX is not acceptable for use as a screening tumor marker, we suggest that the serum concentration of SLX is useful as a staging marker to determine the strategy of treatment.

The discovery, biology, and drug development of sialyl Lea and sialyl Lex

The discoveries of sialylated, fucosylated lacto-, and neolacto-type carbohydrate structures were accomplished with the aid of analytical methods and monoclonal antibodies such as the immunostaining of thin layer chromatograms. Based on the use of such antibodies, these structures, notably sialyl Le(a) and sialyl Le(x), were demonstrated to be highly expressed in many malignant cancers. A diagnostic assay using one of these antibodies (CA19-9) is now established as one of the more commonly used assays for pancreatic and gastrointestinal cancers worldwide. Upon further study, several laboratories have demonstrated that the level of expression of these carbohydrate tumor markers is also positively correlated with patient survival and is a prognostic indicator of metastatic disease. Concurrent with this finding, both sialyl Le(a) and sialyl Le(x) were shown to bind to a family of carbohydrate-binding proteins involved in the extravasation of cells from the bloodstream, called the selectins. Thus, sialyl Le(a) and sialyl Le(x) expressed on cell surfaces play functional roles in medical conditions that require extravasation of cells from the bloodstream which include a wide range of inflammatory diseases and cancer metastasis. Many studies have confirmed the function of sialyl Le(a) and sialyl Le(x) in animal models of these diseases and the inhibition of binding of sialyl Le(a) and sialyl Le(x) to the selectins is a validated drug target in the pharmaceutical industry. Thus, a new class of drugs, arising from the field of glycobiology, is based on the rational design of small molecule drugs that mimic the structures sialyl Le(a) and sialyl Le(x) and can potently inhibit their functional binding to the selectins.

Differences in release mechanisms and distributions for sialyl Le(a) and sialyl Le(x) antigens in colorectal cancer

BACKGROUND

To investigate colorectal cancer-related carbohydrate antigen release and distribution, we evaluated serum levels of sialyl Le(a) (CA19-9) and sialyl Le(x) antigen (SLX) in blood samples obtained from both a peripheral vein and a tumor's draining vein.

METHODS

Blood samples were obtained during surgery from 126 patients. Based on these samples, patients were placed into a high-antigen group, with a concentration above a selected cutoff value, or into a low-antigen group, with a tumor marker concentration below that same value. The blood samples obtained from peripheral veins were designated by the "p" prefix, and samples from drainage veins were designated by the "d."

RESULTS

Serum d-SLX levels were significantly higher than p-SLX levels (P < .0001), although there was no difference between those of d-CA19-9 and p-CA19-9. Only 1 (3.6%) of 28 patients in the high d-CA19-9 group had a low p-CA19-9. In contrast, 6 (33.3%) of 18 patients in the high d-SLX group had low p-SLX levels (P = .0103). Correlations between pathological variables and either p-CA19-9 levels or d-CA19-9 levels were similar. However, both distant metastasis and venous invasion did prove to be independent variables related to d-SLX levels, as shown by logistic regression analysis.

CONCLUSIONS

SLX may drain predominantly via the draining veins of colorectal tumors into portal circulation, whereas CA19-9 may drain via another route.

Immunohistochemical expression of sialyl Lex antigen in relation to survival of patients with colorectal carcinoma

BACKGROUND

The alterations of carbohydrate chains in cancer cell membrane can be related, not only to the formation of tumor-associated antigens, but also to cell biologic significance. There is, furthermore, a possibility of their relationship to tumor metastatic behavior and subsequent survival of patients with cancer. Recent clinical studies elucidated that a carbohydrate antigen, sialyl Lex, is a useful tumor marker in colorectal cancer. However, the sialyl Lex antigen immunoreactivity in colorectal carcinoma in relation to patient survival is unknown. The aim of the study was to elucidate whether sialyl Lex expression in tumors was correlated with patient survival.

METHODS

Immunohistochemical expression of sialyl Lex antigen, as detected by monoclonal antibody CSLEX1, was studied in 175 specimens of primary colorectal carcinoma from 120 patients who received radical surgery.

RESULTS

The positive expression of sialyl Lex was observed in 87 of 120 patients (72.5%). There was no statistically significant association between the negative or positive of sialyl Lex and clinicopathologic factors, excluding Dukes stage and histologic type. The difference between overall 5-year survival of patients with sialyl Lex-negative tumors and that of patients with sialyl Lex-positive tumors (81.2% versus 60.6%) was statistically significant (P = 0.0263). In proportion to staining intensity that was expressed as a score based on the percentage of the total field stained positive with CSLEX1, 5-year survival of patients indicated a worse outcome (P = 0.0113). The prognostic value was then studied in a Cox regression model. Dukes stage had the strongest association with patient survival, whereas sialyl Lex expression was found to be the second-ranking parameter.

CONCLUSIONS

When examining the expression of sialyl Lex antigen, as detected by monoclonal antibody CSLEX1, clinically useful information for patient survival after radical resection of colorectal cancer is given.