Silver stained nucleolar organizer region proteins and Helix pomatia agglutinin immunostaining in esophageal carcinoma: correlated prognostic factors

Validation of a simple avidin-biotin detection method for Helix pomatia lectin (HPA) binding as a prognostic marker in cancer

Helix pomatia lectin (HPA) binding is a marker of metastatic competence in several human cancers. The altered cellular glycosylation detected by HPA is of clinical interest and functional significance, but research has been hampered by uncertainty over appropriate and accessible histochemical methods. Most studies have employed a complex multi-layered detection system localising binding of unconjugated HPA by layering with a polyclonal antibody to HPA, a biotinylated secondary antibody against the first antibody and streptavidin peroxidase. This detection system is sensitive and yields accurate prognostic information, but is lengthy and requires antibodies against HPA that are not widely available. A simpler technique, that uses peroxidase-labelled HPA is inappropriate as the carbohydrate-combining characteristics of the lectin are altered, and the prognostic significance of lectin binding is lost. Therefore a valid alternative, simple and accessible technique is required. In the present study, we compare the results of labelling of HPA binding using the complex multi-layered detection system with a simple avidin-biotin method. In a series of 101 breast cancers, both methods gave comparable results. Therefore, the avidin-biotin method appears to be appropriate for studies on HPA binding to detect altered glycoforms in cancer. It is hoped that its adoption may encourage research into this clinically significant alteration in cellular glycosylation.

GalNAc glycoprotein expression by breast cell lines, primary breast cancer and normal breast epithelial membrane

Over-expression of N-acetylgalactosamine glycoproteins as detected by binding of the lectin from Helix pomatia (HPA), is associated with metastatic competence and poor patient prognosis in a range of human adenocarcinomas. These glycoproteins remain poorly characterised, and their functional role has yet to be elucidated. This study describes characterisation of a range of human breast/breast cancer cell lines for the expression of the N-acetylgalactosaminylated glycoproteins of interest, and their comparison with normal breast epithelium and a range of clinical breast carcinoma samples. Confocal and light microscopy studies revealed cytochemical HPA-binding patterns consistent with a fundamental disruption in normal glycobiosynthetic pathways attending increasing metastatic potential. We report the most complete comparative analysis of HPA-binding ligands from cultured breast cells, clinical breast carcinoma samples and normal breast epithelium to date. Lectin blotting identified 11 major HPA-binding glycoprotein bands common to both clinical tumour samples and breast cell lines and 6 of these bands were also expressed by samples of normal breast epithelium, albeit at much lower levels. Moreover, very marked quantitative but not qualitative differences in levels of expression consistent with metastatic capability were noted.

N-acetylgalactosamine, N-acetylglucosamine and sialic acid expression in primary breast cancers

Binding of the lectin from Helix pomatia (HPA), which recognises N-acetylgalactosamine and N-acetylglucosamine glycans, is a predictor of metastasis and poor prognosis in a number of human adenocarcinomas, including breast cancer. The glycoproteins to which it binds in these tumours have been only partially characterised, and the mechanisms underlying their biosynthesis remain unknown. In this study, 111 primary breast cancers were assessed for binding of HPA and labelling characteristics were compared directly with those of Dolichos biflorus agglutinin and soybean agglutinin, both of which also recognise N-acetylgalactosamine, Griffonia simplicifolia agglutinin II, which recognises N-acetylglucosamine, and Limax flavus agglutinin, Sambucus nigra agglutinin and Maackia amurensis lectin I, all of which recognise sialic acids. Results indicate that the HPA-binding partners expressed by cancer cells are predominantly N-acetylgalactosamine glycans, but some recognition of N-acetylglucosamine species is also likely. There was no evidence to support the hypothesis that overexpression of these moieties results from failure in sialylation. Alternative mechanisms, for example alterations in levels of activity of appropriate glycosyl transferases or disruption in transport and processing mechanisms leading to failure of normal chain extension of glycans may be responsible, and these are areas that warrant further investigation.

Prognosis of esophageal squamous cell carcinoma: analysis of clinicopathological and biological factors

OBJECTIVE

Esophageal squamous cell carcinoma (ESCC) is rather common among the Chinese, but the therapeutic outcome is dismal. Knowledge of the prognostic factors in cancerous patients may influence therapeutic strategy. However, systemic analyses of clinicopathological and biological factors for patients with ESCC are few, and the results are controversial.

METHODS

Between 1985 and 1996, 117 patients undergoing en bloc esophagectomy and gastric substitution were enrolled. None had neoadjuvant treatment. Postoperative adjuvant therapy was provided for patients at and beyond stages IIa. Clinical responses were followed routinely. Flow cytometry was used to measure DNA ploidy and synthesis-phase fraction (SPF) of the resected esophageal tissues from all patients. Immunohistochemistry was also used to examine the expression of proliferating cell nuclear antigen (PCNA), epidermoid growth factor receptor (EGFR), HER-2/neu, and p53 in the pathological sections. Clinical correlation was evaluated by chi2 with Fisher's exact test, and survival by log-rank test.

RESULTS

The overall survival rates were 74% for 1 yr, 48% for 3 yr, and 38% for 5 yr. TNM tumor staging, the number of diseased lymph nodes (N < or = 3 or N > 3), degree of cell differentiation, DNA ploidy, SPF, and lymphovascular invasion were more useful than biological markers, such as PCNA, EGFR, HER-2/neu, and p53, for the prognosis of ESCC. Multivariate analysis revealed significant correlation of tumor staging and number of diseased lymph nodes with patient survival after surgery.

CONCLUSIONS

En bloc esophagectomy may provide a rather satisfactory survival rate for patients with early stage ESCC. However, for patients with distant lymph node metastasis and those with more than three lymph nodes involved, radical surgical resection, even combined with postoperative chemoradiotherapy, cannot improve survival. The prognostic value of biological markers, including PCNA, EGFR, HER-2/neu, and p53, however, is limited.

Evaluation of argyrophilic nucleolar organizer regions (AgNORs) in oral carcinomas in relation to human papillomavirus infection and cytokinetics

The numbers of argyrophilic nucleolar organizer regions (AgNORs) were quantified in oral carcinomas (n = 39) with or without human papillomavirus (HPV) infection. The AgNOR counts of the HPV-positive samples (7.15 +/- 2.13) were not significantly (P = 0.09) higher than those of the HPV-negative ones (6.16 +/- 1.89). Furthermore, the lesions infected with multiple HPV types had greater counts than those with HPV type 16/18 infection alone. Significant differences were observed between the mean counts of the poorly (10.50 +/- 0.54), moderately (7.31 +/- 1.07) and well- (5.12 +/- 0.85) differentiated carcinomas. The mean AgNOR numbers in the oral carcinomas at TNM stages III/IV were found to be significantly (P < 0.01) higher than the numbers in corresponding stage II lesions. Cytokinetics of the lesions assessed by the bromodeoxyuridine (Brdu) labelling index (LI%) showed a linear correlation (r = 0.91; P < 0.0001) with their respective mean AgNOR counts.

Proliferative activity of esophageal carcinomas and their lymph node metastases: comparison using argyrophilic nucleolar organizer region staining

BACKGROUND

Many reports have concluded that quantification of the argyrophilic nucleolar organizer regions (AgNORs) measures proliferative activity and is a prognostic indicator in malignant disease. This retrospective study set out to evaluate the relationship between the AgNORs of the primary tumors and those of lymph node metastases in esophageal carcinoma.

METHODS

Using a one-step silver staining technique, AgNORs were counted in surgical specimens from 54 patients with squamous cell carcinomas.

RESULTS

The AgNOR scores of the lymph nodes metastases were significantly lower than those of the primary tumor (P = 0.0001). In 53 of 54 cases (98%), the AgNOR scores in the nodal metastases were lower than those of the primary tumor. The survival of 22 patients with AgNOR scores > or =4.0 for the primary tumor was significantly less than that of 32 patients with AgNOR scores <4.0 for the primary tumor (P = 0.0014).

CONCLUSIONS

The AgNOR score of the lymph node metastases had no prognostic significance. The AgNOR score of esophageal primary cancer reflects the prognosis of patients. Scores for lymph node metastases were lower and did not reflect prognosis. The lower score in the lymph node metastases may result from the antitumor activity of macrophages in the lymph nodes.

Is the binding of the lectin Helix pomatia agglutinin (HPA) of prognostic relevance in tumours of the upper aerodigestive tract?

The lectin Helix pomatia agglutinin (HPA) has been used as a prognostic indicator in a number of clinical studies including those of breast, colorectal and gastric cancer. Binding of HPA to tissue sections was associated with a bad prognosis indicating that the carbohydrate residue recognized by this lectin is linked to metastasis. In order to investigate whether HPA binding is also of prognostic relevance in squamous cell carcinomas of the upper aerodigestive tract, 53 tumours of this region were stained with HPA. Almost all tumours (95%) bound HPA to various degrees and hence HPA binding is of no prognostic relevance in this group of tumours. These findings indicate a fundamental difference in the role of carbohydrate residues in metastasis between squamous cell carcinoma (as in our study) and in tumours derived from glandular tissues such as breast, colon and stomach.